Large gems are rare and most fluorite stones used in jewelry are ... In the past, moldavite has also been known as chrysolite. Raw moldavite has a rippled, flattened shape, so jewelry makers ...

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 ...