Most people think of the Big Four: diamonds, emeralds, rubies and sapphires. However, it might surprise you to know that there are precious stones that are rarer and more expensive than these ...

It's an open-pit mine, formed around a kimberlite pipe, a rare type of volcanic rock formation that can contain high ...

GIA would rate the highest-quality gemstones as Type I, while most individual companies would issue a AAA designation. These are the 10 most valuable gemstones in the world: Matlins says 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 ...

High-quality black opal can cost over $10,000 per carat, making it one of the world's most expensive gemstones. Over 90% of black opals come from Australia, but they aren't easy to find.

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The collection features more than 1,800 carats of the most precious kind of colour ... “We work with an abundance of different precious gems on a daily basis,” explains Geffroy.