tag:theconversation.com,2011:/fr/topics/crystals-21654/articlesCrystals – The Conversation2024-02-26T13:38:23Ztag:theconversation.com,2011:article/2228512024-02-26T13:38:23Z2024-02-26T13:38:23ZHow is snow made? An atmospheric scientist describes the journey of frozen ice crystals from clouds to the ground<figure><img src="https://images.theconversation.com/files/576863/original/file-20240220-22-v6kq2o.jpg?ixlib=rb-1.1.0&rect=22%2C5%2C3764%2C2055&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some parts of the U.S. see well over 100 inches (2.5 meters) of snow per year.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/downhill-sledging-royalty-free-image/488074477?phrase=sledding+in+snow">Edoardo Frola/Moment Open via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<p><strong>How is snow made? – Tenley, age 7, Rockford, Michigan</strong></p>
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<p>The thought of snow can conjure up images of powdery slopes, days out of school or hours of shoveling. For millions of people, it’s an inevitable part of life – but you may rarely stop to think about what made the snow.</p>
<p>As a <a href="https://www.eaps.purdue.edu/people/profile/ablanch.html">professor of atmospheric and planetary sciences</a>, <a href="https://scholar.google.com/citations?user=xClwTzUAAAAJ&hl=en&oi=ao">I’ve studied how ice crystals floating</a> in the sky become the snow that coats the ground.</p>
<p>It all starts in the clouds.</p>
<p>Clouds form when air near the Earth’s surface rises. This happens when sunlight warms the ground and the air closest to it, just like the Sun can warm your face on a cold winter day. </p>
<p>As the slightly warmer air rises, it cools – and the water vapor in that rising air condenses to form liquid water or water ice. From that, <a href="https://climatekids.nasa.gov/cloud-formation/#:%7E">a cloud is born</a>. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/Cf6El0mI1fM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">You need just two things for snow to form.</span></figcaption>
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<h2>Endless pathways</h2>
<p>When temperatures are well below freezing on the ground, the clouds are primarily made of water in the form of ice. Under 32 degrees Fahrenheit – that’s zero degrees Celsius – the frozen water molecules arrange themselves into a hexagonal, or six-sided, crystalline shape. As ice crystals grow and clump together, they become too heavy to stay aloft. With the help of gravity, they begin to fall back down through and eventually out of the cloud.</p>
<p>What these ice crystals look like once they reach land depends on the temperature and humidity of the atmosphere. As the humidity – or the amount of water vapor in the cloud – increases, some of the ice crystals will grow intricate arms at their six corners. That branching process creates what we think of as the <a href="https://www.timeforkids.com/g2/snowflake-science-g2-5-plus/?rl=en-500">characteristic shapes of snowflakes</a>. </p>
<p>No two ice crystals take the same path through a cloud. Instead, every ice crystal experiences different temperatures and humidities as it travels through the cloud, whether going up or down. The ever-changing conditions, combined with the infinite number of paths the crystals could take, result in a unique growth history and crystalline shape for each and every snowflake. This is why you’ve likely heard the saying, “<a href="https://www.willyswilderness.org/post/no-two-snowflakes-are-alike-it-s-actually-true">No two snowflakes are exactly alike</a>.” </p>
<p>Many times, these differences are visible to the naked eye; sometimes a microscope is required to tell them apart. Either way, scientists who study clouds and snow can examine a snowflake and ultimately understand the path it took through the cloud to land on your hand. </p>
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<a href="https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Snow crystals attached to a window." src="https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=636&fit=crop&dpr=1 600w, https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=636&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=636&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=799&fit=crop&dpr=1 754w, https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=799&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/576901/original/file-20240220-23-n5kry6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=799&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">It takes approximately one hour for a snowflake to reach the ground.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/snowflakes-royalty-free-image/158720307?phrase=snowflakes">LiLi/iStock via Getty Images Plus</a></span>
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<h2>Liquid water as glue</h2>
<p>When snow falls from the sky, you don’t usually see individual ice crystals, but rather clumps of <a href="https://scied.ucar.edu/learning-zone/storms/snowflakes">crystals stuck together</a>. One way ice crystals aggregate is through what’s called mechanical interlocking. When ice crystals bump into each other, crystals with intricate branches and arms intertwine and stick to others. </p>
<p>This mechanism is the main sticking process in cooler, drier conditions – what people call a “<a href="https://compuweather.com/the-important-difference-between-wet-snow-and-dry-snow/">dry snow</a>.” The result is a snow perfect for skiing, and easily picked up by the wind, but that won’t hold together when formed into a snowball. </p>
<p>The second way to stick ice crystals together is to warm them up a bit. When ice crystals fall through a region of cloud or atmosphere where the temperature is slightly above freezing, the edges of the crystals start to melt. Just a tiny bit of liquid water allows ice crystals that bump into each other to stick together very efficiently, almost like glue. </p>
<p>The result? Large clumps of ice crystals falling from the sky, what we call a “<a href="https://www.acurite.com/blog/types-of-snow.html">wet snow</a>” – less than ideal for hitting the slopes but perfect for building a snowman. </p>
<p>Snow formed in clouds typically reaches the ground only in winter. But almost all clouds, no matter the time of year or location, <a href="https://scijinks.gov/clouds/">contain some ice</a>. This is true even for clouds in warm tropical regions, because the atmosphere above us is much colder and can reach temperatures below freezing even on the warmest of days. In fact, scientists who study weather discovered that clouds containing ice produce more rain than those that don’t contain any ice at all.</p>
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<p class="fine-print"><em><span>Alexandria Johnson receives funding from NASA. </span></em></p>There are an infinite number of paths an ice crystal can take before you touch it.Alexandria Johnson, Professor of Atmospheric and Planetary Sciences, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2132022023-11-20T13:15:30Z2023-11-20T13:15:30ZHow do crystals form?<figure><img src="https://images.theconversation.com/files/557894/original/file-20231106-25-rk3zxx.jpg?ixlib=rb-1.1.0&rect=33%2C0%2C5595%2C3713&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Two crystalline materials together: kyanite (blue) embedded in quartz (white).</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/bladed-crystals-of-kyanite-in-quartz-from-brazil-news-photo/869774444">Photo 12/Universal Images Group via Getty Images</a></span></figcaption></figure><figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=293&fit=crop&dpr=1 600w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=293&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=293&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=368&fit=crop&dpr=1 754w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=368&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/281719/original/file-20190628-76743-26slbc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=368&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<p><em><a href="https://theconversation.com/us/topics/curious-kids-us-74795">Curious Kids</a> is a series for children of all ages. If you have a question you’d like an expert to answer, send it to <a href="mailto:curiouskidsus@theconversation.com">curiouskidsus@theconversation.com</a>.</em></p>
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<p><strong>How do crystals form? – Alyssa Marie, age 5, New Mexico</strong></p>
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<p>Scientifically speaking, the term “crystal” refers to any solid that has an <a href="https://theconversation.com/why-does-nature-create-patterns-a-physicist-explains-the-molecular-level-processes-behind-crystals-stripes-and-basalt-columns-186433">ordered chemical structure</a>. This means that its parts are arranged in a precisely ordered pattern, like bricks in a wall. The “bricks” can be <a href="https://australian.museum/learn/minerals/what-are-minerals/crystal-shapes/">cubes or more complex shapes</a>.</p>
<p>I’m <a href="https://scholar.google.com/citations?user=EqUjQbwAAAAJ&hl=en">an Earth scientist and a teacher</a>, so I spend a lot of time thinking about minerals. These are solid substances that <a href="https://www.britannica.com/science/mineral-chemical-compound">are found naturally in the ground</a> and can’t be broken down further into different materials other than <a href="https://www.youtube.com/watch?v=wzTRPlG1L0o">their constituent atoms</a>. Rocks are mixtures of different minerals. <a href="https://www.geologyin.com/2016/03/what-is-difference-between-minerals-and.html">All minerals are crystals</a>, but not all crystals are minerals. </p>
<p>Most rock shops sell mineral crystals that occur in nature. One is <a href="https://theconversation.com/not-so-foolish-after-all-fools-gold-contains-a-newly-discovered-type-of-real-gold-161819">pyrite, which is known as fool’s gold</a> because it looks like real gold. Some shops also feature showy, human-made crystals such as <a href="https://www.zmescience.com/feature-post/natural-sciences/geology-and-paleontology/rocks-and-minerals/the-bismuth-crystal-why-it-looks-so-amazingly-trippy-and-why-its-actually-a-big-deal-for-science/">bismuth</a>, a natural element that forms crystals when it is melted and cooled. </p>
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<a href="https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A dark gray rock with a large concentration of shiny yellow material covering part of its surface." src="https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=453&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=453&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=453&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=569&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=569&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557895/original/file-20231106-267473-4zr8g4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=569&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Pyrite in black shale rock from a quarry in Indianapolis, Ind.</span>
<span class="attribution"><a class="source" href="https://flic.kr/p/uJq9jj">James St. John/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>Why and how crystals form</h2>
<p>Crystals grow when molecules that are alike get close to each other and stick together, forming chemical bonds that act like Velcro between atoms. Mineral crystals cannot just start forming spontaneously – they need special conditions and a <a href="https://www.thoughtco.com/definition-of-nucleation-605425">nucleation site</a> to grow on. A nucleation site can be a rough edge of rock or a speck of dust that a molecule bumps into and sticks to, starting the crystallization chain reaction.</p>
<p>At or near the Earth’s surface, many molecules are dissolved in water that flows through or over the ground. If there are enough molecules in the water that are alike, they will separate from the water as solids – a process called precipitation. If they have a nucleation site, they will stick to it and start to form crystals. </p>
<p>Rock salt, which is actually <a href="https://www.britannica.com/science/halite">a mineral called halite</a>, grows this way. So does <a href="https://www.britannica.com/science/travertine">another mineral called travertine</a>, which sometimes forms flat ledges in caves and around hot springs, where water causes chemical reactions between the rock and the air. </p>
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<a href="https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="White rock terraces around a vent in the earth's surface releasing steam." src="https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/557876/original/file-20231106-23-phmp31.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Travertine ledges at Mammoth Hot Springs in Yellowstone National Park in Wyoming. Terraced pools form due to deposition of travertine from the hot spring fluids as they cool and release carbon dioxide.</span>
<span class="attribution"><a class="source" href="https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/thumbnails/image/P7190038.JPG">USGS</a></span>
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<p>You can make “<a href="http://www.sciencekidsathome.com/science_experiments/growing_stalactites.html">salt stalactites</a>” at home by growing salt crystals on a string. In this experiment, the string is the nucleation site. When you dissolve Epsom salts in water and lower a string into it, then leave it for several days, the water will slowly evaporate and leave the Epsom salts behind. As that happens, salt crystals precipitate out of the water and grow crystals on the string.</p>
<p>Many places in the Earth’s crust are hot enough for <a href="https://www.britannica.com/science/magma-rock">rocks to melt into magma</a>. As that magma cools down, mineral crystals grow from it, just like water freezing into ice cubes. These mineral crystals form at much higher temperatures than salt or travertine precipitating out of water. </p>
<h2>What crystals can tell scientists</h2>
<p>Earth scientists can learn a lot from different types of crystals. For example, the presence of certain mineral crystals in rocks can reveal the rocks’ age. This dating method is called <a href="https://www.britannica.com/science/geochronology">geochronology</a> – literally, measuring the age of materials from the Earth. </p>
<p>One of the most valued mineral crystals for geochronologists is <a href="https://geology.com/minerals/zircon.shtml">zircon</a>, which is so durable that it quite literally stands the test of time. The <a href="https://www.si.edu/newsdesk/releases/earths-oldest-minerals-date-onset-plate-tectonics-36-billion-years-ago">oldest zircons ever found</a> come from Australia and are about 4.3 billion years old – almost as <a href="https://www.amnh.org/exhibitions/darwin/the-world-before-darwin/how-old-is-earth">old as our planet itself</a>. Scientists use the chemical changes recorded within zircons as they grew as a reliable “clock” to <a href="https://knowablemagazine.org/article/physical-world/2021/keeping-time-zircons">figure out how old the rocks containing them are</a>.</p>
<p>Some crystals, including zircons, have growth rings, like the <a href="https://naturalsciences.org/calendar/news/science-at-home-tree-rings/">rings of a tree</a>, that form when layers of molecules accumulate as the mineral grows. These rings can tell scientists all kinds of things about <a href="https://theconversation.com/1-000-year-old-stalagmites-from-a-cave-in-india-show-the-monsoon-isnt-so-reliable-their-rings-reveal-a-history-of-long-deadly-droughts-189222">the environment in which they grew</a>. For example, changes in pressure, temperature and magma composition can all result in growth rings.</p>
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<a href="https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="White rectangular feldspar crystals with faintly visible growth rings are prominent against grey granodiorite rock." src="https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=530&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=530&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=530&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=666&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=666&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559134/original/file-20231113-25-cx8jko.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=666&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Feldspar crystals with growth rings in granodiorite rock near Squamish, British Columbia.</span>
<span class="attribution"><span class="source">Natalie Bursztyn</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Sometimes mineral crystals grow as high pressure and temperatures within the Earth’s crust change rocks from one type to another in a process called <a href="https://www.amnh.org/exhibitions/permanent/planet-earth/how-do-we-read-the-rocks/three-types/metamorphic">metamorphism</a>. This process causes the elements and chemical bonds in the rock to rearrange themselves into new crystal structures. Lots of spectacular crystals grow in this way, including <a href="https://geology.com/minerals/garnet.shtml">garnet</a>, <a href="https://geology.com/minerals/kyanite.shtml">kyanite</a> and <a href="https://geology.com/minerals/staurolite.shtml">staurolite</a>.</p>
<h2>Amazing forms</h2>
<p>When a mineral precipitates from water or crystallizes from magma, the more space it has to grow, the bigger it can become. There is a <a href="https://cen.acs.org/physical-chemistry/geochemistry/Naicas-crystal-cave-captivates-chemists/97/i6">cave in Mexico full of giant gypsum crystals</a>, some of which are 40 feet (12 meters) long – the size of telephone poles.</p>
<p>Especially showy mineral crystals are also valuable as gemstones for jewelry once they are cut into new shapes and polished. The highest price ever paid for a gemstone was $71.2 million for the <a href="https://www.npr.org/sections/thetwo-way/2017/04/05/522739361/pink-star-diamond-sells-for-71-million-smashing-auction-record">CTF Pink Star diamond</a>, which went up for auction in 2017 and sold in less than five minutes.</p>
<hr>
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<p><em>And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.</em></p><img src="https://counter.theconversation.com/content/213202/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Natalie Bursztyn does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There are a lot of myths about crystals − for example, that they are magical rocks with healing powers. An earth scientist explains some of their amazing true science.Natalie Bursztyn, Lecturer in Geosciences, University of MontanaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1900372022-10-10T12:23:44Z2022-10-10T12:23:44ZThe 5,000-year history of writer’s block<figure><img src="https://images.theconversation.com/files/488140/original/file-20221004-18-u6rppp.jpg?ixlib=rb-1.1.0&rect=344%2C278%2C4071%2C3088&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The romantic image of the writer doesn't do justice to the tedious reality of churning out words, one after another.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/surreal-image-of-a-white-cloud-covering-a-womans-royalty-free-image/1309875407?phrase=writer's block art&adppopup=true">fcscafeine/iStock via Getty Images</a></span></figcaption></figure><p>Ann Patchett, who has written eight novels and five books of nonfiction, says that when faced with writer’s block, sometimes it seems that the muse has “<a href="http://www.annpatchett.com/titles#/thisisthestoryofahappymarriage/">gone out back for a smoke</a>.” </p>
<p>It doesn’t matter whether you’re an award-winning novelist or a high schooler tasked with writing an essay for English class: The fear and frustration of writing doesn’t discriminate. </p>
<p>My most recent book, “<a href="https://broadviewpress.com/product/a-writing-studies-primer/">A Writing Studies Primer</a>,” includes a chapter on gods, goddesses and patron saints of writing. When conducting research, I was struck by how writers have consistently sought divine inspiration and intercession.</p>
<p>It turns out that frustrated writers who pine for a muse or help from above are adhering to a 5,000-year-old tradition. </p>
<h2>The first writers look to the skies</h2>
<p>The first writing system, <a href="https://www.britannica.com/topic/cuneiform">cuneiform</a>, arose in Sumer around 3200 BC to keep track of wheat, transactions, real estate and recipes. Scribes used clay tablets to record the information – think of them as early spreadsheets. </p>
<p>Originally the Sumerian goddess of grain, <a href="https://www.worldhistory.org/Nisaba/">Nisaba</a> became associated with writing. She was depicted holding a gold stylus and clay tablet. </p>
<p>As it was common for people to adopt a god or goddess for their professions, a new class of scribes latched onto Nisaba. Practice tablets from <a href="https://www.jstor.org/stable/367648">schools that trained young scribes</a> invoke her name – “Praise be to Nisaba!” Poets trumpeted her influence and <a href="https://twitter.com/anctxtmodtablet/status/1097890316458360832">credited her for giving beautiful handwriting</a> to diligent students. </p>
<p>Her Egyptian counterpart was <a href="https://ancientegyptonline.co.uk/seshat/">Seshat</a>, whose name <a href="https://www.worldhistory.org/Seshat/">translates to</a> “female scribe.”</p>
<figure class="align-right ">
<img alt="Stone carving of woman holding a pen." src="https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1006&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1006&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488164/original/file-20221004-14-hoc6qr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1006&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In Luxor, Egypt, there’s an engraving of Seshat on a statue of Pharaoh Ramses II.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Luxor_temple_16.jpg">Jon Bodsworth/Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>Identifiable by a stylized papyrus as her headdress and a stylus in her right hand, Seshat guided the reed pens of scribes as priests communicated with the divine.</p>
<p>Writing was all about communicating with the gods, and the Greeks and Romans continued this tradition. They turned to the nine daughters of Zeus and Mnemosyne, known collectively as <a href="https://www.ancient-origins.net/myths-legends-europe/nine-muses-0013523">the Muses</a>. Calliope stands out most notably, not only because a musical instrument was named after her, but also because she was considered the foremost of the sisters for her eloquence. </p>
<p>The Muses <a href="https://www.wsj.com/articles/SB124242927020125473">have since evolved</a> into one overarching “muse” that serves as a source of inspiration.</p>
<h2>Global gods and goddesses of writing</h2>
<p>Gods and other legendary figures of writing are not limited to Western civilization. </p>
<p>In China, the historian Cangjie, who lived in the 27th century B.C., is said to have created the <a href="https://www.ewccenter.com/cangjie-and-the-invention-of-chinese-characters">characters of the Chinese language</a>. Legend has it that he was inspired by the pattern of veins on a turtle. (Back then, the Chinese <a href="https://www.worldhistory.org/Oracle_Bones/">often wrote on turtle shells</a>.) </p>
<p>A <a href="https://www.newworldencyclopedia.org/entry/Fu_Xi">competing story</a> says that cultural folk hero Fuxi and his sister Nüwa created the system of Chinese characters circa 2000 B.C. Yet it is Cangjie’s name that lives on in the Cangjie Input Method, which refers to the system that allows Chinese characters <a href="https://www.cangjieinput.com/?lang=en">to be typed using a standard QWERTY keyboard</a>. </p>
<p>In India, writers still invoke the elephant-headed Hindu god <a href="https://www.denverartmuseum.org/en/blog/ganesha-chathurthi-birth-elephant-headed-god">Ganesha</a> <a href="https://www.thestatesman.com/features/common-writing-rooms-well-known-authors-lord-ganesh-1502544876.html">before putting ink to paper</a>. Known as a remover of obstacles, Ganesha can be especially meaningful for those struggling with writer’s block. There’s also <a href="https://www.worldhistory.org/Sarasvati/">Saraswati</a>, the Hindu goddess of learning and the arts, who’s renowned for her eloquence. </p>
<p>In Mesoamerica, Mayan culture looked to <a href="https://www.britannica.com/topic/Itzamna">Itzamná</a> as the deity who provided the pillars of civilization: writing, calendars, medicine and worship rituals. His depiction as a toothless and wise old man signaled that he was not to be feared, an important characteristic for someone promoting an anxiety-inducing process like writing. </p>
<h2>Enter the patron saints</h2>
<p>In Christianity, <a href="https://theconversation.com/who-are-patron-saints-and-why-do-catholics-venerate-them-148508">patron saints</a> are exemplars or martyrs who serve as role models and heavenly advocates. Various groups – professions, people with a certain illness and even entire nations – will adopt a patron saint.</p>
<p>Within the Catholic Church, a range of patron saints can serve as inspiration for writers. </p>
<p><a href="https://theconversation.com/st-brigid-the-compassionate-sensible-female-patron-saint-of-ireland-gets-a-lot-less-recognition-than-st-patrick-176659">St. Brigid of Ireland</a>, who lived from 451 to 525, is the patron saint of printing presses and poets. A contemporary of the better-known <a href="https://theconversation.com/10-things-to-know-about-the-real-st-patrick-92253">St. Patrick</a>, St. Brigid established a monastery for women, which included a school of art that became famous for its handwritten, decorative manuscripts, particularly the <a href="http://www.kildarearchsoc.ie/the-book-of-kildare/">Book of Kildare</a>. </p>
<p>Following St. Brigit in Ireland is St. Columba, who lived from 521 to 597 and founded the influential abbey at Iona, an island off the coast of Scotland. A renowned scholar, St. Columba transcribed over 300 books over the course of his life.</p>
<p>The influence of patron saints dedicated to literacy – reading and writing – continued long after the Middle Ages. In 1912, the <a href="https://www.css.edu/">College of Saint Scholastica</a> was founded in Minnesota in tribute to <a href="https://d.lib.rochester.edu/teams/text/whatley-saints-lives-in-middle-english-collections-life-of-st-scholastica-introduction">Scholastica</a> (480-543), who with her twin brother, Benedict (died in 547), enjoyed discussing sacred texts. Both Italian patron saints came to be associated with books, reading and schooling.</p>
<h2>Objects charged with power</h2>
<p>Some writers may think supernatural figures seem a bit too far removed from the physical world. Fear not – there are magical objects that they can touch for inspiration and help, such as talismans. Derived from the ancient Greek word telein, which means to “fulfill,” it was an object that – like an amulet – protected the bearer and facilitated good fortune. </p>
<p>Today, you can buy talismans drawn on ancient Celtic symbols that purport to help with the writing process. <a href="https://www.moonlightmysteries.com/pewter-talisman-for-poets-writers-and-actors/">One vendor promises</a> “natural inspiration and assist in all of your writing endeavors.” Another supplier, <a href="https://www.magickalneeds.com/product/talisman-for-poets/">Magickal Needs</a>, advertises a similar product that supposedly helps “one find the right word at the most opportune moment.” </p>
<p>Others turn to crystals. A <a href="https://www.etsy.com/au/listing/831873886/healing-crystals-for-writers-writers">writer’s block crystals gift set</a> available through Etsy offers agate, carnelian, tiger eye, citrine, amethyst and clear quartz crystals to help those struggling to formulate sentences.</p>
<h2>What makes a writer?</h2>
<p>What drove the creation of divine beings and objects that can inspire and intercede on the behalf of writers?</p>
<p>To me, it’s no mystery why writers have sought divine intervention for 5,000 years. </p>
<p>Sure, tallying counts of sheep or bushels of grain might seem like rote work. Yet early in the development of writing systems, the physical act of writing was exceedingly difficult – and one of the reasons schoolchildren prayed for help with their handwriting. Later, the act of creation – coming up with ideas, communicating them clearly and engaging readers – could make writing feel like a herculean task. Ironically, this complex skill does not necessarily get easier, even with lots of practice. </p>
<p>The romantic image of the <a href="https://theconversation.com/genius-in-the-garret-or-member-of-the-guild-60175">writer in the garret</a> doesn’t do justice to the tedious reality of churning out words, one after another. </p>
<p>In his memoir “<a href="https://stephenking.com/works/nonfiction/on-writing-a-memoir-of-the-craft.html">On Writing</a>,” Stephen King reflected, “Amateurs sit and wait for inspiration, the rest of us just get up and go to work.” At the suggestion of a friend, the writer Patchett attached a <a href="http://www.annpatchett.com/titles#/thisisthestoryofahappymarriage/">sign-in sheet to the door of her writing room</a> to ensure she wrote every day.</p>
<figure class="align-center ">
<img alt="Man sitting on chair with legs crossed clasping hands near face." src="https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488166/original/file-20221004-19-q3cyfh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">For novelist Stephen King, writing is a matter of discipline and routine.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/horror-writer-stephen-king-at-the-w-hotel-wednesday-morning-news-photo/563552651?phrase=%22stephen%20king%22&adppopup=true">Richard Hartog/Los Angeles Times via Getty Images</a></span>
</figcaption>
</figure>
<p>No matter how accomplished a writer, he or she will inevitably struggle with writer’s block. Pulitzer Prize−winning author John McPhee, who began contributing to The New Yorker in 1963, details his writer’s block in a <a href="https://www.newyorker.com/magazine/2013/04/29/draft-no-4">2013 article</a>: “Block. It puts some writers down for months. It puts some writers down for life.” Another famous writer for The New Yorker, Joseph Mitchell, was struck by <a href="https://www.bbc.com/news/av/magazine-32602862">writer’s block in 1964</a> and simply sat and stared at his typewriter for 30 years.</p>
<p>I’ve even wrestled with this article, writing and rewriting it in my head a dozen times before actually typing the first word.</p>
<p>Poet and satirist Dorothy Parker <a href="https://www.nytimes.com/interactive/projects/cp/obituaries/archives/dorothy-parker">once said</a>, “I hate writing; I love having written.”</p>
<p>You and me both, Dorothy.</p><img src="https://counter.theconversation.com/content/190037/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joyce Kinkead does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Since the earliest days of the written word, students and scholars have pleaded for help from higher powers, a sure sign that writing and frustration always have – and always will – go hand in hand.Joyce Kinkead, Distinguished Professor of English, Utah State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1901342022-09-12T20:27:36Z2022-09-12T20:27:36ZFolded diamond has been discovered in a rare type of meteorite. How is this possible?<figure><img src="https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&rect=19%2C118%2C4373%2C2845&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.eurekalert.org/multimedia/948716">Nick Wilson</a></span></figcaption></figure><p>A “folded diamond” doesn’t sound entirely plausible. But that’s exactly what we’ve found inside a rare group of meteorites known as ureilites, which likely came from the mantle of a <a href="https://en.wikipedia.org/wiki/Dwarf_planet">dwarf planet</a> or very large asteroid that was destroyed 4.56 billion years ago in a giant collision.</p>
<p>Within these space rocks, we found layered diamonds with distinctive fold patterns. Our discovery is published today in the journal <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.2208814119">Proceedings of the National Academy of Sciences</a>.</p>
<p>Now of course, everyone knows diamond is <a href="https://pursuit.unimelb.edu.au/articles/diamonds-the-hard-facts">the hardest naturally occurring material</a>, so the obvious question was – how on Earth (or in space!) could a folded diamond possibly form?!</p>
<p>This was exactly the sort of curiosity-piquing observation that sends scientists diving down rabbit holes for months on end.</p>
<h2>A new analysis technique</h2>
<p>Carbon, one of the most abundant elements in the universe, can form all kinds of structures. Among the more familiar ones are graphite and, of course, diamond. But there’s also an unusual hexagonal form of diamond known as lonsdaleite, which has been suggested to be even harder than standard cubic diamonds.</p>
<figure class="align-center ">
<img alt="A red, yellow and purple coloured marbling on a turquoise background" src="https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&rect=19%2C118%2C4373%2C2845&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483643/original/file-20220909-20-4vcbiw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Distribution of lonsdaleite in yellow, diamond in pink, iron in red, silicon in green, and magnesium in blue within a meteorite detected by electron probe microanalysis.</span>
<span class="attribution"><a class="source" href="https://www.eurekalert.org/multimedia/948716">Nick Wilson</a></span>
</figcaption>
</figure>
<p>Our team includes a bunch of people who drive development of advanced analysis techniques. At CSIRO, Nick Wilson, Colin MacRae and Aaron Torpy developed a new approach in electron microscopy to map the distribution of diamond, graphite and lonsdaleite in the meteorites. </p>
<p>When our mapping suggested the folded diamond might actually be lonsdaleite, we – Dougal McCulloch, Alan Salek and Matthew Field at RMIT – performed a more detailed investigation via a method called high-resolution transmission electron microscopy (<a href="https://en.wikipedia.org/wiki/Transmission_electron_microscopy">TEM</a>).</p>
<p>The results were exciting: we had found some of the largest lonsdaleite crystallites (microscopic crystals) ever discovered, about 1 micrometre across. So, those intriguing fold shapes were composed of polycrystalline lonsdaleite, meaning they were made from numerous tiny crystals.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Folded structures visible in a greyscale image and the same visible in purple underneath" src="https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=833&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=833&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=833&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1047&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1047&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483167/original/file-20220907-16-j5r5p8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1047&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Microscope photo (top) and cathodoluminescence map (bottom) of folded lonsdaleite, purple, with diamond in green-yellow (field of view 0.25 mm).</span>
<span class="attribution"><span class="source">PNAS, 2022</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Reconstructing the cataclysm</h2>
<p>And there was even more. We found the lonsdaleite had been partially converted to diamond and graphite, giving us clues to the sequence of events that had happened in the meteorites. Follow-up work at the Australian Synchrotron by Helen Brand confirmed this result. </p>
<p>By comparing the diamond, graphite and lonsdaleite across 18 different ureilite meteorites, we started to form a picture of what probably happened to produce the folded structures we found. At the first stage, graphite crystals folded deep inside the mantle of the asteroid thanks to high temperatures causing the other surrounding minerals to grow, pushing aside the graphite crystals. (You can see this in the schematic below.)</p>
<figure class="align-center ">
<img alt="Complex chart showing the stages of an asteroid crumbling apart" src="https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=458&fit=crop&dpr=1 600w, https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=458&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=458&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=576&fit=crop&dpr=1 754w, https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=576&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/483169/original/file-20220907-24-5dem3n.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=576&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Schematic indicating the timing and positions of diamond and lonsdaleite formation as the ureilite parent asteroid was partially destroyed by a giant impact (Ol, olivine; Px, pyroxene).</span>
<span class="attribution"><span class="source">PNAS, 2022</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The second stage happened in the aftermath of the gigantic collision that catastrophically disrupted the ureilite parent asteroid. <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/maps.13755">Evidence in the meteorites</a> suggested the disruption event produced a rich mix of fluids and gases as it progressed.</p>
<p>This mix then caused lonsdaleite to form by replacement of the folded graphite crystals, almost perfectly preserving the intricate textures of the graphite. Of course, it’s not actually possible to <em>fold</em> lonsdaleite or diamond – it formed by replacement of pre-existing shapes.</p>
<p>We think this was driven by the hot fluid mix as pressure and temperature dropped immediately after the cataclysm. Then, shortly after, diamond and graphite partially replaced the lonsdaleite as the fluid further decompressed and cooled to form a gas mixture.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-rare-minerals-form-when-meteorites-slam-into-earth-105129">How rare minerals form when meteorites slam into Earth</a>
</strong>
</em>
</p>
<hr>
<h2>Manufacturing clues from nature</h2>
<p>The process is quite similar to a process used to manufacture diamonds known as <a href="https://www.youtube.com/watch?v=YTML-JGRfMc">chemical vapour deposition</a>. These manufactured diamonds are widely used in industry today, particularly for cutting and grinding because diamond is so hard. The difference is that we think the lonsdaleite replaced the shaped graphite at moderately higher pressures than those normally used to grow diamonds, from a <a href="https://en.wikipedia.org/wiki/Supercritical_fluid">supercritical fluid</a> rather than a gas. </p>
<p>So, nature appears to have given us clues on how to make shaped ultra-hard micro machine parts! If we can find a way to replicate the process preserved in the meteorites, we can make these machine parts by replacement of pre-shaped graphite with lonsdaleite.</p>
<p>Being able to study these weird folded diamonds was possible because lead author Andrew Tomkins had time to follow his nose – we call this type of research “curiosity-driven science”. However, although <a href="https://news.harvard.edu/gazette/story/2018/04/most-transformative-meds-originate-in-curiosity-driven-science-evidence-says/">curiosity-driven science produces important breakthroughs</a>, it isn’t normally funded by major funding agencies. They like to see well thought-out details for grand projects that already have a solid foundation of prior research.</p>
<p>We think a good way to boost Australia’s innovation would be to provide recognised science innovators a small grant annually to spend on research as they see fit; no questions asked, no justification or follow-up required.</p>
<p>For curiosity-driven research like our project, scientists need a small amount of time (and money) that can be spent with complete freedom; this produces <a href="https://theconversation.com/the-secret-to-creativity-according-to-science-89592">the creativity</a> that drives innovation. You never know what else we might find out there.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-created-diamonds-in-mere-minutes-without-heat-by-mimicking-the-force-of-an-asteroid-collision-150369">We created diamonds in mere minutes, without heat — by mimicking the force of an asteroid collision</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/190134/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Tomkins receives funding from the Australia Research Council. </span></em></p><p class="fine-print"><em><span>Alan Salek receives a RSS Scholarship. </span></em></p><p class="fine-print"><em><span>Dougal McCulloch receives funding from Australian Research Council.</span></em></p>An unusual folded shape in a meteorite prompted scientists to dive deep into a rabbit hole – discovering a potential new way to make specially shaped diamonds in the lab.Andrew Tomkins, Geologist, Monash UniversityAlan Salek, PhD Researcher, RMIT UniversityDougal McCulloch, Professor, RMIT UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1860292022-07-06T12:19:30Z2022-07-06T12:19:30ZWhat’s behind the enduring popularity of crystals?<figure><img src="https://images.theconversation.com/files/472090/original/file-20220701-23-s4ooix.jpg?ixlib=rb-1.1.0&rect=579%2C36%2C4111%2C2676&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Proponents claim the stones can promote health and well-being. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/sisters-meditating-with-healing-crystals-rooftop-royalty-free-image/1280567102?adppopup=true">janiecbros/Getty Images</a></span></figcaption></figure><p>As New York City mayor Eric Adams attends ribbon cuttings, <a href="https://nypost.com/2022/06/12/nyc-mayor-eric-adams-booed-while-marching-in-pride-parade/">marches in parades</a> and <a href="https://autos.yahoo.com/york-mayor-bulldozes-hundreds-illegal-204200186.html">bulldozes dirt bikes</a>, he wears an <a href="https://www.nytimes.com/2021/11/03/style/eric-adams-style.html">energy stone bracelet</a> that his supporters gave him. <a href="https://www.politico.com/news/magazine/2022/03/11/eric-adams-nyc-mayor-profile-00016106">In a recent interview</a>, Adams discussed his belief that New York City has a “special energy” because it sits atop a store of rare gems and stones – the so-called “<a href="https://nypost.com/2022/06/09/mayor-eric-adams-says-healing-crystals-give-nyc-good-vibes/">Manhattan schist</a>,” which is over 450 million years old and contains over 100 minerals.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1535034393030545425"}"></div></p>
<p>Adams isn’t the only one imbuing rocks with metaphysical significance. During the first year of the pandemic, the <a href="https://www.theguardian.com/us-news/2020/oct/31/us-crystal-gem-boom-people-looking-for-healing">crystal industry boomed</a>, with customers hoping the gems might relieve their anxiety. </p>
<p>Some people might be confused about the allure of these stones. But crystal enthusiasts aren’t deviants. Current ideas about crystals come from a larger tradition called “<a href="https://yalebooks.yale.edu/book/9780300136159/republic-mind-and-spirit/">metaphysical religion</a>” that has always been part of the American spiritual landscape.</p>
<h2>More than rocks</h2>
<p>Technically, <a href="https://nature.berkeley.edu/classes/eps2/wisc/Lect4.html">a crystal</a> is any matter with a repeating pattern of atoms or molecules. The crystals for sale in shops are known as <a href="https://www.sciencedirect.com/topics/chemistry/euhedral-crystal">euhedral crystals</a> because they have well-defined surfaces, or “faces.”</p>
<p><a href="https://news.stanford.edu/2018/08/09/understanding-peoples-obsession-crystals/">For centuries</a>, people have attributed special properties to crystals. Scientist <a href="https://www.google.com/books/edition/The_Demon_haunted_World/ulqPDQAAQBAJ?hl=en&gbpv=1&dq=Sagan+OUr+Demon+Haunted+World&printsec=frontcover">Carl Sagan</a>, in his book “The Demon-Haunted World,” traces their modern popularity to a series of books written in the 1980s by Katrina Raphaell, who founded <a href="https://webcrystalacademy.com/">The Crystal Academy of Advanced Healing Arts</a> in 1986.</p>
<p>Crystals aren’t just eye-catching stones. Quartz is used in electronics because it possesses <a href="https://www.youtube.com/watch?v=wcJXA8IqYl8">piezoelectric properties</a> that cause it to release an electric charge when compressed. But, <a href="https://skepticalinquirer.org/1989/07/crystals/">as skeptics are quick to point out</a>, there is no evidence crystals can bring health, prosperity or any of the other properties that crystal enthusiasts may attribute to them. </p>
<h2>Mining the metaphysical</h2>
<p>Yet crystals are part of a broader tradition called metaphysical religion, <a href="https://yalebooks.yale.edu/book/9780300136159/republic-mind-and-spirit/">a term coined</a> by historian <a href="https://www.religion.ucsb.edu/people/emeriti/catherine-l-albanese/">Catherine Albanese</a>.</p>
<p>Metaphysical religion includes modern <a href="https://www.pewresearch.org/fact-tank/2018/10/01/new-age-beliefs-common-among-both-religious-and-nonreligious-americans/">New Age movements</a>, a nebulous milieu of alternative spiritual beliefs and practices, such as <a href="https://www.psychologytoday.com/us/basics/synchronicity">synchronicity</a> or psychic abilities. Older traditions like <a href="https://hypnosis.edu/history/the-birth-of-mesmerism">Mesmerism</a>, the idea that humans beings emit magnetic energy that can be used for healing, and <a href="https://www.austintexas.gov/sites/default/files/files/Parks/OHenry/spiritualism.pdf">Spiritualism</a>, the belief that mediums can communicate with the dead, also fall under the metaphysical umbrella.</p>
<p>Albanese ascribes four characteristics to metaphysical traditions: a preoccupation with the mind and its powers; “correspondences,” or the idea of hidden connections between things; a tendency to think in terms of energy and movement; and a yearning for salvation understood as “solace, comfort, therapy, and healing.” </p>
<h2>‘Contagious magic’</h2>
<p>Metaphysical ideas about crystals exhibit each of these characteristics.</p>
<p>While crystals are physical objects, not thoughts, many crystal enthusiasts recommend “cleansing” and “charging” crystals <a href="https://themanifestationcollective.co/how-cleanse-charge-crystals-beginner/">through visualization</a> and other meditative techniques. So the mind plays a key role in crystal spirituality, as it does in other forms of metaphysical religion.</p>
<figure class="align-center ">
<img alt="Two masked women walk through a store filled with colorful crystals." src="https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/472112/original/file-20220701-22-57bpnb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Crystal sales soared during the pandemic.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/cheryl-rey-center-manager-of-the-crystalarium-and-abby-news-photo/1234406149?adppopup=true">Genaro Molina/Los Angeles Times via Getty Images</a></span>
</figcaption>
</figure>
<p>Correspondence refers to the belief found in many occult traditions that ordinary things possess secret qualities or connections to other things. A classic example is <a href="https://www.theatlantic.com/health/archive/2018/01/the-new-age-of-astrology/550034/">astrology</a>, which postulates a correspondence between one’s birthday and certain personality traits. Metaphysical claims about crystals also reflect a belief in correspondences. For example, Colleen McCann, a self-described shaman affiliated with the crystal purveyor Goop, <a href="https://nypost.com/2017/10/04/spencer-pratt-and-heidi-montag-order-27k-of-crystals-for-childbirth/">described the positive qualities</a> of different crystals: bloodstones promote good health, rose quartzes help with love, and pink mangano calcites are good for sleep. </p>
<p>Modern crystal enthusiasts often use words like “energy” and “vibrations” that present their ideas in a scientific register. When enthusiasts talk about the energy of crystals – like Eric Adams did – they really mean that it exerts influence within a certain proximity. This is the principle behind <a href="https://www.elle.com/uk/beauty/body-and-physical-health/a28242635/crystal-water-bottle-wellness-trend/">crystal water bottles</a> that can be used to “charge” water with “vibrational energy.”</p>
<p>Stripped of scientific language, the logic of energy and vibrations is another form of what anthropologist <a href="https://www.britannica.com/biography/James-George-Frazer">James Frazer</a> called “<a href="https://www.gutenberg.org/files/3623/3623-h/3623-h.htm#c3section1">contagious magic</a>” found in many cultures, where simply placing one thing next to another is believed to cause an effect.</p>
<h2>A source of stigma</h2>
<p>Finally, metaphysical religion tends to focus on solving problems in this life rather than the hereafter. This includes health and prosperity, but also emotional growth and well-being. Crystal spirituality is certainly centered around these worldly goals. </p>
<p>This is a big distinction from traditions like Christianity that emphasize salvation in heaven. It is also a factor in why metaphysical ideas are stigmatized despite their popularity.</p>
<p>Protestant Christianity, with its emphasis on “sola fides” – faith alone – has historically dismissed many forms of <a href="https://www.tandfonline.com/toc/rfmr20/current">material religion</a>, or objects with religious significance, as superstition. So in a culture shaped by its historically <a href="https://religionnews.com/2021/07/08/survey-white-mainline-protestants-outnumber-white-evangelicals/">Protestant majority</a>, some Americans may be predisposed to look at crystal spirituality as foolish, greedy or even <a href="https://www.bibleinfo.com/en/questions/what-does-bible-say-about-crystals">blasphemous</a>. </p>
<p>But while claims about the hidden properties of crystals lack scientific validation, so do many of the claims of Christianity and other mainstream religions. </p>
<p>From a historical perspective, Adams’ ideas about crystals don’t make him an outlier. As a scholar of religious studies, I see him as a normal part of the American religious landscape.</p><img src="https://counter.theconversation.com/content/186029/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joseph P. Laycock does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Crystals are part of a larger tradition of metaphysical religions that have a long history in the U.S.Joseph P. Laycock, Associate Professor of Religious Studies, Texas State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1618192021-06-27T19:48:55Z2021-06-27T19:48:55ZNot so foolish after all: ‘fool’s gold’ contains a newly discovered type of real gold<figure><img src="https://images.theconversation.com/files/408340/original/file-20210625-13-h5xcss.jpeg?ixlib=rb-1.1.0&rect=8%2C0%2C5982%2C4491&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Uoaei1/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>The mineral pyrite was historically nicknamed <a href="https://www.britannica.com/science/pyrite">fool’s gold</a> because of its deceptive resemblance to the precious metal. The term was often used during the California gold rush in the 1840s because inexperienced prospectors would claim discoveries of gold, but in reality it would be pyrite, composed of worthless iron disulfide (FeS₂). </p>
<p>Ironically, pyrite crystals can contain small amounts of real gold, although it is notoriously hard to extract. Gold hiding within pyrite is sometimes referred to as “invisible gold”, because it is not observable with standard microscopes, but instead requires sophisticated scientific instruments. </p>
<p>It wasn’t until the 1980s when <a href="https://www.researchgate.net/profile/Louis-Cabri/publication/258209241_The_nature_of_invisible_gold_in_arsenopyrite/links/02e7e5273cded2849f000000/The-nature-of-invisible-gold-in-arsenopyrite.pdf">researchers discovered</a> that gold in pyrite can come in different forms – either as particles of gold, or as an alloy, in which the pyrite and gold are finely mixed.</p>
<p>In our new research, <a href="https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G49028.1/604581/A-new-kind-of-invisible-gold-in-pyrite-hosted-in">published in Geology</a>, my colleagues and I discovered a third, previously unrecognised way that gold can lurk inside pyrite. When the pyrite crystal is forming under extreme temperature or pressure, it can develop tiny imperfections in its crystal structure that can be “decorated” with gold atoms.</p>
<h2>What are these ‘crystal defects’?</h2>
<p>The atoms within a crystal are arranged in a characteristic pattern called an atomic lattice. But when a mineral crystal such as pyrite is growing inside a rock, this lattice pattern can develop imperfections. Like many minerals, pyrite is tough and hard at Earth’s surface, but can become more twisty and stretchy when forming deep in the Earth, which is also where gold deposits form. </p>
<p>When crystals stretch or twist, the bonds between neighbouring atoms are broken and remade, forming billions of tiny imperfections called “dislocations”, each roughly 100,000 times smaller than the width of a human hair, or 100 times smaller than a virus particle.</p>
<p>The chemistry of these atomic-scale imperfections is notoriously difficult to study because they are so small, so any impurities are present in absolutely minuscule quantities. Detecting them requires a specialised instrument called an <a href="http://youtube.com/watch?v=CXiDO4vjfVg">atom probe</a>.</p>
<p>An atom probe can analyse materials at extremely high resolution, but its main advantage over other methods is that it allows us to build a 3D map showing the precise locations of impurities within a crystal — something that was never possible before.</p>
<p>Our research reveals that dislocations within pyrite crystals can be “decorated” with gold atoms. This is particularly common where the crystals have been twisted during their history; here, gold can be present at concentrations several times higher than in the rest of the crystal.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Impurities in pyrite crystal" src="https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=765&fit=crop&dpr=1 600w, https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=765&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=765&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=961&fit=crop&dpr=1 754w, https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=961&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/404402/original/file-20210604-15-ferqh6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=961&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Gold (Au) atoms hiding within a pyrite crystal, alongside other imperfections including nickel, copper and bismuth. Scale bar indicates 20 nanometres.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A potential goldmine</h2>
<p>Why should anyone care about something so tiny? Well, it gives interesting insights into how mineral deposits form, and is also a potential boon for the gold mining industry.</p>
<p>Previously, it was suspected that gold in anomalously rich pyrite crystals was in fact made of gold particles formed during a multi-step process, suggesting the pyrite and gold crystallised at different times and then became clumped together. But our discovery that gold can decorate these crystal imperfections suggests that even pyrite crystals with relatively high gold content can form in a single process.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/eureka-x-ray-vision-can-find-hidden-gold-17432">Eureka! X-ray vision can find hidden gold</a>
</strong>
</em>
</p>
<hr>
<p>Our discovery may also help gold miners more efficiently extract gold from pyrite, potentially reducing greenhouse emissions. To extract the gold, the mineral is usually oxidised in large reactors, which uses considerable amounts of energy.</p>
<p>Dislocation sites within crystals could potentially offer an enhanced partial leaching or a target for bacteria to attack and break down the crystal, releasing the gold in a process known as “bio-leaching”, thus potentially reducing energy consumption necessary for extraction. This idea is still untested, but definitely merits investigation.</p>
<p>If it helps pave the way for more sustainable gold-mining methods, then perhaps fool’s gold isn’t so foolish after all.</p>
<p>Perhaps pyrite still lives up to its historic reputation of “fool’s gold” until better, more environmentally sustainable ore processing techniques are developed.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-gold-rushes-helped-make-the-modern-world-91746">How gold rushes helped make the modern world</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/161819/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Denis Fougerouse is affiliated with the School of Earth and Planetary Sciences and The Institute for Geoscience Research at Curtin University. He receives funding from the Australian Research Council. </span></em></p>Fool’s gold, or pyrite, is made of worthless iron disulfide, but can contain tiny amounts of the real thing. Using an ‘atom probe’, research has uncovered a new way gold atoms can hide in pyrite crystals.Denis Fougerouse, Research Fellow, School of Earth and Planetary Sciences, Curtin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1619342021-06-02T14:27:04Z2021-06-02T14:27:04ZGeometrically baffling ‘quasicrystals’ found in the debris of the first-ever nuclear blast<figure><img src="https://images.theconversation.com/files/404021/original/file-20210602-23-j7l21n.jpeg?ixlib=rb-1.1.0&rect=7%2C7%2C1614%2C945&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The heat and pressure generated by a nuclear explosion can produce unusual chemical curiosities. </span> <span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/f/fc/Trinity_Detonation_T%26B.jpg">United States Department of Energy/wikimedia</a></span></figcaption></figure><p>Nuclear detonations unleash an astonishing amount of destructive force. But the extreme <a href="https://www.sciencedirect.com/science/article/pii/B012227410500315X">pressure</a> and <a href="https://www.sciencedirect.com/book/9780128013007/materials-under-extreme-conditions">temperature</a> that they generate also makes nuclear blasts a cauldron of chemical creation, capable of delivering new and surprising scientific discoveries.</p>
<p>In the 1950s, for instance, scientists examining debris from US <a href="https://time.com/4096424/ivy-mike-history/">hydrogen bomb tests</a> found two new elements, which now occupy numbers 99 and 100 in the periodic table. They named them after prominent nuclear scientists: <a href="https://theconversation.com/einsteinium-100-years-after-einsteins-nobel-prize-researchers-reveal-chemical-secrets-of-element-that-bears-his-name-154447">einsteinium</a> for Albert Einstein, and <a href="https://www.britannica.com/science/fermium">fermium</a> for Enrico Fermi.</p>
<p>Now, scientists sifting through debris at the site of the <a href="https://theconversation.com/this-is-what-happened-the-morning-the-first-atomic-bomb-created-a-new-world-142184">first-ever nuclear bomb detonation</a> – held in New Mexico in July 1945 and named <a href="https://www.atomicheritage.org/history/trinity-test-1945">the Trinity test</a> – have unearthed a different chemical oddity. <a href="https://www.pnas.org/content/118/22/e2101350118">In their paper</a>, the researchers report the discovery of a previously unknown type of “<a href="https://www.britannica.com/science/quasicrystal">quasicrystal</a>” – a crystal formation once thought impossible due to its irregular geometric structure.</p>
<h2>What are quasicrystals?</h2>
<p>Quasicrystals were <a href="https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.53.1951">first discovered</a> by material scientist Dan Schechtman in 1984, but were initially seen as highly controversial – even impossible – because their unique form is not allowed by the rules defining crystal structures.</p>
<p>Crystals are composed of units that repeat periodically in three dimensions. A good way to think of this is to picture them in two dimensions. You can tile a floor with certain geometric shapes – like squares, triangles and hexagons – because they tessellate, meaning that they can be slotted together in a repeating pattern with no overlaps or gaps. You can’t do this with pentagonal or heptagonal tiles. They can’t be tessellated, so they’d leave irregular gaps on your floor.</p>
<p>Three dimensional crystal structures adhere to the same rule. The repeating units naturally arrange themselves in a regular pattern – filling up all the available space. A <a href="https://www.sciencedirect.com/topics/chemistry/simple-hexagonal-crystal-system">hexagonal arrangement</a>, for instance, is a typical crystal structure.</p>
<figure class="align-center ">
<img alt="A hexagonal pattern of bonded spheres" src="https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/404044/original/file-20210602-25-6j3u08.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Crystals of ice arrange to form a hexagonal structure.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/8/88/Ice_XI_View_along_c_axis.png">Danski14/wikimedia</a></span>
</figcaption>
</figure>
<p>The general rule is that crystals must have repeating units with 2-fold, 3-fold, 4-fold or 6-fold axes. Here, “fold” means how many times you can rotate the three-dimensional crystal unit so that it looks the same as its starting position – enabling tessellation. The rule means that crystal units with a 5-fold axis (pentagonal) or anything 7-fold and above (heptagonal and beyond) won’t tessellate, and therefore cannot exist.</p>
<h2>Penrose tiling</h2>
<p>This rule held until 1974, when the British mathematical physicist Roger Penrose found a way to cover a two dimensional space like a floor with shapes that <a href="https://link.springer.com/article/10.1007/s11224-020-01669-8">do not repeat periodically</a> – a form of tessellation now called “<a href="https://www.maths.ox.ac.uk/node/865">Penrose tiling</a>”.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/yxlEojkVJ0c?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Penrose tiling uses just two shapes: a kite and a dart.</span></figcaption>
</figure>
<p>These ideas were soon applied to <a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.53.2477">three-dimensional structures</a>, and it was in 1984 that Schechtman published his experimental work on quasicrystals. His discovery won him the <a href="https://www.nobelprize.org/prizes/chemistry/2011/shechtman/facts/">Nobel Prize for Chemistry in 2011</a>. </p>
<p>Over 100 types of quasicrystal have been discovered since, though nearly all of them have been produced in the lab. <a href="https://www.newscientist.com/article/2115570-third-ever-natural-quasicrystal-found-in-siberian-meteorite/">Three exceptions</a>, found <a href="https://www.pnas.org/content/109/5/1396">within the Khatyrka meteorite</a> in north-eastern Russia, may date back to the beginning of our solar system. And now there’s another, which is the oldest existing quasicrystal to have been produced – albeit accidentally – as a result of human activity.</p>
<h2>New quasicrystal</h2>
<p>The new quasicrystal was found within a glassy material called red trinitite, which the scientists sourced from the site of the 1945 nuclear blast. The trinitite was formed at the moment of the Trinity test’s detonation, when the desert sands of New Mexico were thrown up into the air and heated to 8,000°C before raining down as newly synthesised trinitite.</p>
<p>This new quasicrystal is <a href="https://math.wikia.org/wiki/Icosahedron">icosahedral</a> – possessing 20 faces – and is structured with 2-fold, 3-fold and 5-fold symmetry axes. This means that there are three specific perspectives of this complex 3D structure that are repeated identically when it’s rotated: one is repeated twice, one three times, and the other five times. It’s the 5-fold axis – like the two dimensional pentagon we know can’t tessellate – that means the sample is a quasicrystal.</p>
<p>It’s also a unique sample, because the quasicrystal has silicon, calcium and copper in its composition. The copper, which gives the trinitite its red hue, is likely to have found its way into the quasicrystal via a set of transmission lines that ran close to the site of the bomb test and were vaporised along with the sand upon detonation.</p>
<h2>Learning from quasicrystals</h2>
<p>Practically, material scientists are exploring the <a href="http://mcs.open.ac.uk/ugg2/quasi_intro6.shtml">application of quasicrystals</a> to exploit their poor heat conductivity, which is possibly related to their non-periodic structures. They’ve already been used as coatings in <a href="https://www.nature.com/articles/d41586-019-00026-y">non-stick frying pans</a>, for example. Other suggested applications include <a href="https://phys.org/news/2020-09-scientists-capture-polymeric-quasicrystal.html">LED lights</a> and surgical instruments, but their development is at an early stage. </p>
<p>But if more of these crystallographic and chemical curiosities are found in the debris left behind by nuclear bomb tests, studying their composition could also help scientists understand the ferocious forces at play in the heart of nuclear blasts – a place no scientific instrument has yet measured directly.</p><img src="https://counter.theconversation.com/content/161934/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert A Jackson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The quasicrystals were ‘accidentally’ synthesised during the first test of a nuclear bomb in July 1945.Robert A Jackson, Reader, School of Chemical and Physical Sciences, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/905582018-01-24T10:57:45Z2018-01-24T10:57:45ZVolcano crystals could make it easier to predict eruptions<figure><img src="https://images.theconversation.com/files/203195/original/file-20180124-72600-1gdh5au.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/eruption-etna-volcano-february-2017-sicily-747933055?src=1a4rIhrGhgzux4qjzB4Ylw-1-7">Shutterstock</a></span></figcaption></figure><p>Predicting when a volcano is going to explode is a <a href="https://theconversation.com/why-cant-we-predict-when-a-volcano-will-erupt-53898">very difficult task</a>. Every volcano has its own unique and complex maze of tunnels that feed magma to the surface. So even when we detect volcanic activity, it’s very hard to know when the magma will make its way through these tunnels and erupt.</p>
<p>But there’s now a way to assess this process using crystals that grow inside volcanoes and act like a record of its eruption. <a href="https://www.nature.com/articles/s41467-017-02274-w">Our latest study</a> on crystals from Mount Etna in Italy has shown that if new magma arrives in chambers 10km below Etna’s surface, an eruption can follow within two weeks. No wonder the Roman poet Lucretius said Etna “rages with flames from th’ lowest pit of Hell”.</p>
<p>Geologists used to think of the magma below volcanoes as being in a large single chamber, <a href="http://onlinelibrary.wiley.com/doi/10.1029/2011GL048488/full">but modern research</a> shows that feeding systems contain many connected compartments with complex transport routes. We also know what when new magma recharges these volcanic feeding systems it can <a href="https://www.nature.com/articles/267315a0">trigger an eruption</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-cant-we-predict-when-a-volcano-will-erupt-53898">Why can't we predict when a volcano will erupt?</a>
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</em>
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<p>As it moves towards the surface, the newly stirred magma pushes apart the rock, building up pressure beneath the volcano. This produces earthquakes and inflates the volcano’s cone-shaped edifice, effects that can be monitored at the surface or <a href="https://svs.gsfc.nasa.gov/30188">from space with satellites</a>. What’s difficult is knowing if a particular magma recharge will actually translate into an eruption and <a href="https://theconversation.com/magma-refills-could-predict-volcano-eruptions-16212">how much time</a> it will take for the eruption to start.</p>
<p>This is where the crystals <a href="https://www.nature.com/articles/nature10706">can come in</a>. These minerals are called antecrysts (“ante” meaning before) because they often start growing from early magmas thousands of years before the volcano erupts. They grow layer by layer, <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev.earth.35.031306.140211">recording changes</a> in the surrounding magma, like tree rings registering variations in the climate.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=552&fit=crop&dpr=1 600w, https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=552&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=552&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=694&fit=crop&dpr=1 754w, https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=694&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/203199/original/file-20180124-72603-g8vm0e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=694&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Antecryst map.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Laser technology now means we can look into the antecrysts to create maps of the <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1751-908X.2007.00104.x/full">trace chemical elements</a> inside them. This essentially involves firing a grid of laser lines over the antecryst and then using what’s known as a mass spectrometer to analyse the aerosol that is given off and work out what it contains.</p>
<p>This can be used to create a 2D image of the crystal’s composition that can tell us something about <a href="https://www.sciencedirect.com/science/article/pii/S0009254115002831">its history</a>. For example, when old antecryst cores are transported to the surface by newly stirred magma, it generates a distinctive rim on the crystal. The challenge is to extract meaning from these records.</p>
<h2>Mapping Etna</h2>
<p>Using crystal chemical maps from the last 40 years of volcanic activity at Mount Etna, we’ve been able to determine the depth at which the crystals grow but also when new magma began invading the underground volcanic system. We found that this started occurring in the 1970s, coinciding with when the volcano began to <a href="http://www.geo.mtu.edu/volcanoes/boris/mirror/mirrored_html/ETNA_elenco.html">erupt more often</a>, with faster-moving magma and more explosiveness and seismic activity.</p>
<p>The <a href="https://pubs.geoscienceworld.org/gsa/geology/article-abstract/33/10/837/103755">type of contact</a> between the crystal cores and the rims and <a href="https://academic.oup.com/petrology/article/43/12/2279/1512026">thickness of the rims</a> hold information on how much time elapses between the arrival of batches of magma and when an eruption started. This means we can better predict when an eruption is likely to occur after magma is detected at certain points beneath the volcano (in this case, two weeks after arrival at depth).</p>
<p>In this way, carrying out laser surveys of antecrysts from around the world could help volcanologists better understand how magma recharge acts as a trigger for eruptions, and how to interpret monitoring data from active volcanoes. This could create a more accurate process for spotting <a href="http://www.annualreviews.org/doi/abs/10.1146/annurev.earth.33.092203.122459">warning signs</a> and predicting imminent eruptions.</p><img src="https://counter.theconversation.com/content/90558/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Balz Kamber receives funding from Science Foundation Ireland. </span></em></p><p class="fine-print"><em><span>Teresa Ubide receives funding from The University of Queensland, the Australian Geoscience Council and the Australian
Academy of Science. </span></em></p>A new study has found a way to predict eruptions at Mount Etna within two weeks.Balz Kamber, Chair of Geology and Mineralogy, Trinity College DublinTeresa Ubide, Lecturer in Igneous Petrology/Volcanology, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/831482017-08-29T20:10:03Z2017-08-29T20:10:03ZCrystals like you’ve never seen them before: they’re flexible<figure><img src="https://images.theconversation.com/files/183692/original/file-20170829-1549-16d2opx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Crystals are renowned for being hard and brittle. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/crystal-stone-macro-purple-rough-amethyst-416855083?src=0cOiZtc5SlwTEUCsGawH4A-1-57">from www.shutterstock.com</a></span></figcaption></figure><p>You’re already familiar with substances that are crystals - think rock salt, or quartz. Typically, these materials are hard, brittle and inelastic, and crack or shatter irreversibly when struck or bent. </p>
<p>Published this week, our <a href="http://www.nature.com/nchem/journal/vaop/ncurrent/full/nchem.2848.html">new paper</a> describes a new type of crystal: one that is flexible, and that can even be tied in a knot. </p>
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<figcaption><span class="caption">Crystals can be flexible.</span></figcaption>
</figure>
<p>This new development means we can think about new applications for crystals beyond their existing uses, such as in mobile phones and computers. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-we-cant-spin-a-silken-yarn-as-strong-as-a-spider-can-71003">Why we can't spin a silken yarn as strong as a spider can</a>
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</em>
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<h2>It’s all in the structure</h2>
<p>The properties of crystals are due to the way that atoms or molecules are arranged; crystals have infinitely repeating molecular components. As well as defining their physical characteristics, these also result in useful features that underpin a wide variety of modern technologies, such as semiconductors in electronics. </p>
<p>But these physical properties also limit the use of crystals in emerging technologies like flexible electronics and optical devices.</p>
<p>Our new paper shows we can grow elastic crystals about the width of a fishing line and up to five centimetres long. These crystals can be reversibly and repeatedly bent and stretched as much as common plastics like Nylon or polyethylene. They show no signs of breaking or cracking. Remarkably, they also keep the useful properties of crystals. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/183682/original/file-20170829-22730-1b4zzt5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Yes, that’s a crystal. Tied in a knot.</span>
<span class="attribution"><span class="source">Jack Clegg</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>A new kind of crystal</h2>
<p>The crystals that we have prepared fall outside the limits of what have traditionally been considered to be hard and soft matter.</p>
<p>The metal complex we used to make our crystal – copper (II) acetylacetonate – isn’t a new compound: it was first made in the late 1800s. But it’s how the molecules are arranged relative to the shape of the crystal that makes it different. </p>
<p>Using X-rays generated by the <a href="http://www.synchrotron.org.au/">Australian Synchrotron</a>, we were able to <a href="https://images.nature.com/full/nature-assets/nchem/journal/vaop/ncurrent/extref/nchem.2848-s3.mp4">map changes in the structure</a> of the crystals to the atomic level when they were bent. We found that the individual molecules reversibly rotate as they are bent, allowing both the compression and expansion that is required for elasticity. </p>
<p>Understanding the way that the molecules move when the crystals are bent will allow the development of many more examples. While we accidentally discovered the first example of these crystals, we have now made six more examples of flexible crystals containing related molecules. </p>
<h2>Playing with Lego plus cooking</h2>
<p>Making these crystals in the lab is a little bit like playing with Lego combined with cooking. We stick different molecular building blocks together in a flask, and after stirring and letting the liquid solvent evaporate we end up with beautiful flexible crystals. </p>
<p>Because we can control the chemistry of the building blocks on the atomic level we can also control the flexible properties of the crystal on the macro scale.</p>
<p>The method we have developed to measure the changes in the crystals during bending could also be used to explore flexibility in any other crystals. This is an exciting prospect given that there are millions of different types of crystals already known and many more yet to be discovered.</p>
<hr>
<p><em><strong>Read more:</strong> <a href="https://theconversation.com/the-periodic-table-from-its-classic-design-to-use-in-popular-culture-52822">The periodic table from its classic design to use in popular culture</a></em> </p>
<hr>
<p>Bending the crystal changes its optical and magnetic properties, and our next step is to explore these optical and magnetic responses with a view to identifying applications in new technologies.</p>
<h2>New materials, new technologies</h2>
<p>The ability of crystals to bend flexibly has wide-ranging implications. For example, the loss of symmetry when a crystal is bent or twisted means it is no longer strictly a crystal by traditional definitions. </p>
<p>Flexible crystals like these will lead to new hybrid and new smart materials that respond to changes in their environment like temperature, pressure or the application of force for emerging technologies including components of aeroplanes and space craft or parts of sensors and electronic devices.</p>
<p>The research is a joint study between researchers from Queensland University of Technology and The University of Queensland.</p><img src="https://counter.theconversation.com/content/83148/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jack K. Clegg receives funding from The Australian Research Council. </span></em></p><p class="fine-print"><em><span>John McMurtrie receives funding from The Australian Research Council. </span></em></p>It’s a crystal - but not as you’ve seen it before. A new crystal can be bent and flexed, and is expected to deliver new responsive materials for emerging technologies.Jack K. Clegg, A/Prof. of Inorganic Chemistry, The University of QueenslandJohn McMurtrie, Associate Professor of Inorganic Chemistry, Queensland University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/731042017-02-21T12:31:06Z2017-02-21T12:31:06ZTime crystals: how scientists created a new state of matter<figure><img src="https://images.theconversation.com/files/157676/original/image-20170221-18659-1u01flt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock/CatyArte</span></span></figcaption></figure><p>Some of the most profound predictions in theoretical physics, such as <a href="https://theconversation.com/gravitational-waves-found-the-inside-story-54589">Einstein’s gravitational waves</a> or <a href="https://theconversation.com/nobel-prize-in-physics-goes-to-discovery-of-the-higgs-boson-19014">Higgs’ boson</a>, have taken decades to prove with experiments. But every now and then, a prediction can become established fact in an astonishingly short time. This is what happened with “time crystals”, a new and strange state of matter that was theorised, disproved, revamped and finally created in just five years since it was first predicted in 2012.</p>
<p>Crystals, such as diamond and quartz, are made of atoms arranged in a repeating pattern in space. In these new crystals, atoms also follow a repeating pattern, but in time. Because of this weird property, time crystals could one day find applications in revolutionary technologies such as quantum computing.</p>
<p>The story of time crystals begins in 2012 with Nobel Prize winner Frank Wilczek from MIT. As a theoretical physicist and a mathematician, Wilczek made a crucial step in transferring a key property of regular crystals – called <a href="https://plato.stanford.edu/entries/symmetry-breaking/">symmetry breaking</a> – to create the idea of time crystals. </p>
<p>To understand what symmetry breaking is, think of liquid water. In a water droplet, molecules are free to move about and can be anywhere within the liquid. The liquid looks the same in any direction, meaning that it has a high degree of symmetry. If the water freezes to form ice, attractive forces between the molecules force them to rearrange into a crystal, where molecules are spaced at regular intervals. But this regularity means that the crystal isn’t as symmetrical as the liquid, so we say the symmetry of the liquid has been broken when freezing into ice.</p>
<p>Symmetry breaking is one of the most profound concepts in physics. It is behind the formation of crystals, but also appears in many other fundamental processes. For example, the famous <a href="https://theconversation.com/explainer-what-is-mass-49299">Higgs mechanism</a>, which explains how subatomic particles come to acquire mass, is a symmetry breaking process. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/157679/original/image-20170221-18646-1p0228t.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Crystals have regular but asymmetrical atomic arrangements.</span>
<span class="attribution"><span class="source">Shutterstock/SmirkDingo</span></span>
</figcaption>
</figure>
<p>Back in 2012, Wilczek came up with <a href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.109.160401">a tantalising idea</a>. He wondered if, in the same way that a crystal breaks symmetry in space, it would be possible to create a crystal breaking an equivalent symmetry in time. This was the first time the idea of a time crystal was theorised. </p>
<p>Such an object would have an intrinsic time regularity, equivalent to the crystal’s regular pattern in space. For a time crystal, the pattern would be a continuous change back and forth in one of its physical properties, a kind of heartbeat that repeats forever, a bit like a perpetual motion machine. </p>
<p>Perpetual motion machines, which are machines that can work indefinitely without an energy source, <a href="https://futurism.com/what-physics-says-about-perpetual-motion-machines-free-energy-r/">are forbidden by the laws of physics</a>. Wilczek recognised this oddity of his time crystal theory and, in 2015, another group of theoretical physicists showed a perpetual motion crystal would indeed <a href="journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.251603">be impossible</a>. </p>
<p>But this was not the end of the story. In 2016, <a href="journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.090402">new research</a> showed that time crystals could still exist in theory, but only if there was some external driving force. The idea was that the time regularity would be somehow dormant, hidden from view, and that adding a little energy would bring it to life and unveil it. This solved the paradox of perpetual motion, and brought new hopes for the existence of time crystals. </p>
<p>Then, in the summer of 2016, the conditions to create and observe time crystals were laid out in an article in the <a href="https://arxiv.org/abs/1608.02589">online arXiv repository</a>, and later published in the peer-reviewed journal <a href="journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.030401">Physical Review Letters</a>. The researchers studied how a special property of particles known as <a href="https://www.scientificamerican.com/article/what-exactly-is-the-spin/">quantum spin</a> could be repeatedly reversed by an external force at regular intervals. They predicted that if they did this to a set of particles, the interactions between the particles would produce their own oscillations in the spin, creating a “driven” time crystal.</p>
<p>In a matter of months, two different experimental groups had taken on the challenge to create the time crystals in the laboratory. One of the teams <a href="https://arxiv.org/abs/1609.08684">fired laser pulses</a> at a train of <a href="https://en.wikipedia.org/wiki/Ytterbium">ytterbium</a> atoms that produced oscillations in the atoms’ properties, at different intervals from the pulses. This meant that the ytterbium atoms were behaving as a time crystal.</p>
<p>The other team focused on an entirely different system, consisting of impurities in a diamond crystal. They used microwaves to <a href="https://arxiv.org/abs/1610.08057">disturb the impurities</a> at well-defined intervals, and observed the same type of time-crystal oscillations as the first team. At last, time crystals had been created and Wilczek’s main ideas proven true. </p>
<h2>Crystal future</h2>
<p>The prediction, realisation and discovery of time crystals opens a new chapter in quantum mechanics, with questions about the properties of this newly found state of matter and whether time crystals might occur in nature.</p>
<p>The symmetry-breaking properties of ordinary crystals have lead to the creation <a href="http://metamaterials.duke.edu/research/acoustic-metamaterials">of phononic</a> and <a href="https://www.photonics.com/Article.aspx?AID=61665">photonic metamaterials</a>, deliberately designed materials that selectively control acoustic vibrations and light that can be used to boost the performance of <a href="http://physicsworld.com/cws/article/news/2017/feb/15/blocking-the-symmetry-of-motion">prosthetics</a>, or to increase the efficiency of <a href="https://www.eurekalert.org/pub_releases/2017-02/uoc--mc021617.php">lasers and fibre-optics</a>. So the time symmetry-breaking properties of time crystals will likely find their way into equally novel fields, such as chrono-metamaterials for quantum computing, which uses the inherent properties of atoms to store and process data.</p>
<p>The story of time crystals started with a beautiful idea by a theoretical physicist, and now has culminated its first chapter with conclusive experimental evidence after a mere five years. Far from <a href="https://theconversation.com/is-this-the-end-of-particle-physics-as-we-know-it-lets-hope-not-42849">coming to an end</a> as scientists prove their big theories, it seems physics is more alive than ever.</p><img src="https://counter.theconversation.com/content/73104/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rodrigo Ledesma-Aguilar does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Scientists theorised, disproved, revamped and finally created a bizarre new form of matter in just five years.Rodrigo Ledesma-Aguilar, Senior Lecturer in Physics, Northumbria University, NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/538362016-01-29T16:10:10Z2016-01-29T16:10:10ZDid the Vikings use crystal ‘sunstones’ to discover America?<figure><img src="https://images.theconversation.com/files/109688/original/image-20160129-3876-1d52dte.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Leif Erikson discovers America</span> <span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Vinland#/media/File:Christian-krohg-leiv-eriksson.jpg">Christian Krogh/Wikimedia Commons</a></span></figcaption></figure><p><a href="https://www.academia.edu/186935/Who_Was_Wulfstan">Ancient records</a> tell us that the intrepid Viking seafarers who discovered Iceland, Greenland and eventually North America <a href="http://sciencenordic.com/how-vikings-navigated-world">navigated using</a> landmarks, birds and whales, and little else. There’s little doubt that Viking sailors would also have used the positions of stars at night and the sun during the daytime, and <a href="https://arago.elte.hu/sites/default/files/Errors-on-Viking-sun-compass-hint-at-alternative-purpose_%20PhysOrg.pdf">archaeologists have discovered</a> what appears to be a kind of Viking navigational sundial. But without magnetic compasses, like all ancient sailors they would have struggled to find their way once the clouds came over.</p>
<p>However, there are also several reports in Nordic sagas and other sources of a sólarsteinn “sunstone”. <a href="http://www.vsnrweb-publications.org.uk/Raudulfs%20thattr.%20text.pdf">The literature</a> doesn’t say what this was used for but it has sparked decades of research examining if this might be a reference to a more intriguing form of navigational tool.</p>
<p>The idea is that the Vikings may have used the interaction of sunlight with particular types of crystal to create a navigational aid that may even have worked in overcast conditions. This would mean the Vikings had discovered the basic principles of measuring polarised light centuries before they were explained scientifically and which are today used to identify and measure different chemicals. Scientists are now getting closer to establishing if this form of navigation would have been possible, or if it is just a fanciful theory. </p>
<h2>Scattering and polarisation</h2>
<p>To understand how this might have worked, we need to understand some things about the way light, and particularly sunlight, can be affected. Light coming from the sun is scattered and polarised by the atmosphere. This occurs when light is absorbed and re-emitted with the same energy by air molecules and by different amounts depending on the light’s wavelength. The blue end of the light spectrum is scattered more than the red, as explained in theory developed by the British physicist Lord Rayleigh in the 19th century. Scattering by particles in the atmosphere explains why the <a href="https://theconversation.com/explainer-why-is-the-sky-blue-10821">sky appears blue</a>.</p>
<p>More importantly, scattered light waves are <a href="https://theconversation.com/polarised-light-and-the-super-sense-you-didnt-know-you-had-44032">also polarised</a> to a certain extent. That means they vibrate in one plane rather than in all directions at once. The amount of polarisation a beam of sunlight undergoes depends on its angle to the viewer and whether the light has been further scattered by cloud and other particles that cause depolarisation.</p>
<p>Around the coastline of Norway and Iceland are found crystalline chunks of calcium carbonate known as calcite or Iceland spar. When polarised sunlight enters a calcite crystal, something very interesting happens. Calcite is strongly birefringent, meaning that it splits light passing through it into two separate waves that are bent or refracted in different directions and with different intensities, although the total intensity will be constant.</p>
<p>This means that objects viewed through a calcite crystal appear in double. More importantly for our purposes, the different intensities of the two light waves depends on how the original light is polarised and the position and orientation of the crystal compared to the light source.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/109683/original/image-20160129-3901-zgghtm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Crystal clear double vision.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Tourmaline and cordierite are crystals with similar properties, except instead of splitting light like calcite they are strongly dichroic. This means they absorb one component of polarisation more strongly than the other. Again, the dichroic properties depend on how the original light is polarised and the position and orientation of the crystal compared to the light source.</p>
<p>So, in theory at least, examining how sunlight passes through one of these crystals – and appropriately calibrated – could be used as a guide for sailors to estimate the position of the sun. This could then allow them to determine the direction of geographic north – even without understanding the scientific principles behind these phenomena. </p>
<p>If we make the huge assumption that the Vikings had these sunstone crystals on board their ships and, more importantly, knew what they were doing with them, the question this is whether the difference in the light would be detectable to their eyes? And would it be detectable with enough accuracy (after errors because of imperfections in the crystals and depolarisation), to be used as a navigation aid even in overcast conditions.</p>
<h2>Testing the theory</h2>
<p>The latest in an impressive roster of publications on the subject recently appeared in <a href="http://dx.doi.org/10.1098/rsos.150406">Royal Society Open Science</a>, seeking to address this precise question. Gabor Horvath and his colleagues looked at whether the optical signals from these three types of crystal would be strong enough to be detected and with enough accuracy to predict the position of the sun under a cloudy sky.</p>
<p>To do this, they simulated the conditions, including the position of the sun, of a Viking voyage between Norway, southern Greenland and Newfoundland. They found that in clear skies, where the degree of polarisation was high, all three crystals did show sufficient signal and good accuracy. In light cloudy conditions where the degree of polarisation was somewhat reduced but still relatively high, cordierite and tourmaline functioned better than calcite.</p>
<p>Only very pure calcite (with optical impurities removed) performed to a similar level as the other two crystals. If sunlight polarisation was very low, calcite appeared to give the best results in predicting the sun’s position through clouds. And in thicker cloudy conditions or fog, the errors of measurement became too high for all three crystals.</p>
<p>Horvath’s team are now looking at the further errors involved in predicting the position of geographical north using this information. If the method does not work under cloudy conditions when using the kind of imperfect crystals the Vikings would likely have possessed, the whole theory is probably wrong. And on clear days it would have been easier just to use calibrated sundials.</p>
<p>But if the researchers establish that sunstones could have accurately been used to determine the direction of geographic north, then the idea looks feasible. Then all that will remain to finally prove this fascinating theory will be to find a Viking ship with a calibrated sunstone in it. That, however, may take some time.</p><img src="https://counter.theconversation.com/content/53836/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stephen Harding does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A bold theory suggests the Vikings may have used a mysterious method of studying sunlight to navigate the oceans.Stephen Harding, Professor of Applied Biochemistry, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/489402015-10-19T03:37:58Z2015-10-19T03:37:58ZExplainer: a new nanochip that will detect bacterial infections in 15 minutes<figure><img src="https://images.theconversation.com/files/98672/original/image-20151016-25138-1rphveg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nanotechnology that can detect illnesses will become available next year. </span> <span class="attribution"><span class="source">shutterstock</span></span></figcaption></figure><p>A new <a href="http://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=1723">device</a> – a <a href="http://encyclopedia2.thefreedictionary.com/Biological+Sensors">biological sensor</a> inside a nanochip – that can detect bacterial infections in ten to 15 minutes will become available in 2016. </p>
<p>Devised by a team of scientists from South Africa’s Stellenbosch University, the device is currently being patented. The <a href="http://www.tia.org.za/about-us">Technology Innovation Agency</a> has funded a prototype in preparation for commercialisation by April 2016.</p>
<p>Pathogenic organisms infect about <a href="https://books.google.co.za/books?id=tWWA_3s1lwcC&pg=PA183&lpg=PA183&dq=Pathogenic+organisms+infect+about+%5B250+million&source=bl&ots=x52cwqG1fq&sig=LwZPFhyv7eie9bR-l1czw9pRuf4&hl=en&sa=X&redir_esc=y#v=onepage&q=Pathogenic%20organisms%20infect%20about%20%5B250%20million&f=false">250 million</a> people a year. At least 8%, around 20 million people, die. Early detection of infections can prevent many deaths.</p>
<p>Since the nanochip was announced as a project of the university in September 2014, progress has been made in developing additional sensing mechanisms, enhancing its capabilities.</p>
<h2>How the nanochip was born</h2>
<p>The nanochip for early detection of infection came after a chance meeting between the author and microbiologist <a href="http://www.innovus.co.za/pages/posts/meet-our-researcher-professor-leon-dicks-microbiology-76.php">Leon Dicks</a>, an expert in the field of superconductors and nanoelectrical devices. </p>
<p>While discussing individual current research, we agreed to work to find a way of detecting infections early and accurately.</p>
<p>The basis for our research was <a href="http://www.explainthatstuff.com/piezoelectricity.html">piezoelectricity</a>, which is how crystals convert mechanical energy into electricity or vice-versa. </p>
<p>The sensor that was developed for this purpose comprises a nanochip stacked with zinc oxide molecules on top of each other to create millions of nanowires.</p>
<p>Piezoelelectric energy plays a key role in the identification process. When certain materials, such as zinc oxide wires, are squeezed or pressed they generate an electric charge in response to applied mechanical stress. The slightest disturbance in the structure of the nanowires on the chip leads to piezoelectric energy. This is then converted to electrical energy and amplified to produce a voltage reading.</p>
<p>Microorganisms, such as bacteria, are known as flagellated micro-organisms. Flagella are almost like little tails that are fixed to the organism. Vigorous movement of the flagella is used to propel the organisms at quite a high speed. These movements disturb the nanowires to generate an electronic signal due to the piezoelectric effect.</p>
<h2>Biological flavour</h2>
<p>The nanochip will use a flexible substrate that would generate electricity by movement of a person’s body, thereby, for example, charging the battery of an electronic device, such as a <a href="http://www.medicinenet.com/pacemaker/page3.htm#what_is_a_pacemaker">pacemaker</a>.</p>
<p>To be able to use the nanochip for infection detection, a biological flavour was added to the sensor and application by adding a lure that would attract specific bacteria. A <a href="http://benthamscience.com/journals/current-nanoscience/volume/10/issue/6/page/827/">silicon chip</a>, measuring 1cm², was stacked with zinc oxide molecules on top of each other to create a nanowire.</p>
<p>The concept was tested by attaching lysozyme molecules to the tip of each nanowire. Bacteria buster <a href="http://dictionary.reference.com/browse/lysozyme">lysozyme</a> was chosen for the test because it is in abundance in human saliva, tears and milk. </p>
<p>As soon as lysozyme-specific antibodies sticks to the nanowires, the zinc oxide molecules were realigned. This movement was detected by a change in the electrical output in 15 minutes. The lysozome-specific antibodies stuck to the lysozome molecules. The movement caused by this attraction and attachment process disturbed the nanowires, resulting in an electric signal being generated.</p>
<h2>What we found</h2>
<p>The investigation showed that the zinc oxide nanowires are promising piezoelectric nanoforce transducers that may be developed into biomolecular detection systems.</p>
<p>Binding of antibodies to the biosensor surface indicates a strong piezoelectric effect on the biosensing signal. The designed nanoforce biosensor showed a linear relationship with respect to voltage output and antibody concentration.</p>
<p>The <a href="http://www.sciencedirect.com/science/article/pii/S0925400514007655">results</a> showed that it is possible to detect biomolecular interactions by coupling the piezotronic and biosensing characteristics of zinc oxide nanowires.</p>
<h2>What does this mean</h2>
<p>A patient swallowing a capsule containing a nanochip for detecting infections caused by pathogens, such as E.coli, V.cholera or Salmonella will know immediately the cause of their illness. </p>
<p>The production of antibodies is the natural mechanism for humans and animals to fight bacterial infections. Antibodies are specific to pathogens and by choosing the specific antibodies to attach to the piezoelectric sensor, it becomes possible to detect the specific pathogen that is tested for. </p>
<p>The possibilities of utilising this concept for the detection of different infections or the presence of different types of bacteria are thus legion.</p>
<p>Using an antigen-specific nanochip could also provide an excellent platform for testing water quality in remote rural areas.</p>
<p>Testing for certain bacterial infections does not necessarily have to be done inside the patient’s body. A drop of blood or a patient’s sputum could be tested for diseases, such as tuberculosis, on a handheld nanochip testing station outside the body.</p>
<p>Furthermore, the nanochip biological sensor method could play an important role in the detection and control of post-operative infection. Surgeons could implant a nanochip during open heart or orthopaedic surgery. By doing this they are mindful of infections where early detection and treatment is key.</p>
<h2>Benefits</h2>
<p>The use of piezoelectric energy is not the only possible vehicle for detection of disease. The sensor also uses the piezoelectric effect to detect the pathogens by attaching antibodies to the sensor. The sensor attracts the specific pathogens.</p>
<p>Other mechanisms can be used to detect the presence of pathogens in a patient’s body. These mechanisms also use antibodies as bait.</p>
<p>The method of detection can be optical, when attracted pathogens interfere with the transmission of light through an optical fibre coated with a scaffolding structure with antibodies attached to it. It may be resistive when the pathogens alter the resistance of a sensing structure. It is capacitive when the pathogens change the dielectric constant of the sensing structure.</p>
<p>It may be resistive when the pathogens alter the resistance of a sensing structure. It is capacitive when the pathogens change the dielectric constant of the sensing structure.</p>
<p>We look at different sensing structures, obviously with the antibodies attached, to use different sensing techniques. Other methods, including optical, resistive and capacitive sensing techniques, are currently being looked at.</p>
<p>Apart from the lives saved by early detection and treatment of infections, the nanochip biological sensor approach could become a less expensive diagnostic method if manufactured on a large scale. Costs would be reduced.</p><img src="https://counter.theconversation.com/content/48940/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Willie Perold receives funding from the National Research Foundation (NRF) and the Technology Innovation Agency (TIA). </span></em></p>A novel approach to detect bacterial infections in 10-15 minutes is expected to become commercially available next year.Willie Perold, Vice Dean (Research), Faculty of Engineering, Stellenbosch UniversityLicensed as Creative Commons – attribution, no derivatives.