Some diamonds come from depths of more than 650km. Tiny imperfections in these gems give us clues about what's happening in Earth's hidden geological layers.
Why is jewellery so important to the story of human evolution? Because it provides a public message – even to people we don't know.
What makes a stone a gem? It boils down to a few key qualities: beauty and durability. But opal, the national gemstone of Australia, is an anomaly - it's soft.
Why do we attach sentimental value to objects and other things?
Namibian crafters may be on the verge of commercial success with the carving of the Makalani nut. But they are not sure if they want to commercialise operations.
Problems occur when a country falls in love with gold, and silver might be about to get a boost from proposed solutions.
More than 95% of industrial diamonds are synthetic so why aren't more people using them in engagement rings?