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 ...

The rarest gemstone in the world is considered to be a transparent mineral of reddish-orange ... The rarest mineral in the world is kyawthuite (Photo: mindat) Cost of kyawthuite The cost of the new ...