Male monks were not the sole producers of books throughout the Middle Ages.
Whether forged by geological processes or laboratory techniques, diamonds are diamonds. Their unique properties mean they have applications that are not bling-related as well.
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.
Zirconia is a mineral with a crystal structure made from the elements zirconium and oxygen. It looks pretty like diamond, but is only worth a fraction of the value.
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.
The world's biggest known sapphire was formed and shaped by natural processes millions of years ago.