When you think of expensive gemstones, what comes to mind? Most people think of the Big Four: diamonds, emeralds, rubies and sapphires. However, it might surprise you to know that there are ...

Narrator: High-quality black opal can cost over $10,000 per carat, making it one of the world's most expensive gemstones. But mining black opal isn't easy. After investing tens of thousands of ...

A single curling stone certified for the Olympics costs over $600. That makes a full set of 16 stones worth $9,600. Since 2006, every stone used in the Olympic Winter Games has come from Kays of ...