Most gems form in a number of places below the Earth's surface and are then brought to the surface through processes like volcanic eruption, mountain building or erosion. At that point, they are ...

When I was a kitten, I loved collecting rocks and gems. So, I was very excited to talk about your question with my friend Johannes Haemmerli. He studies minerals at Washington State University.

Very few gems can withstand the intense pressure of Earth's mantle, but some require it to crystallize. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it ...