Following is a transcript of the video. 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.

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.

Opals are formed when water and silicon dioxide ... Rubies can be exceptionally expensive. One ruby, weighing 25.59 carats and set between four small, 2.4- to 2.7-carat diamonds, sold for a ...

"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Opals may have been around for thousands of years, but they’re having a major resurgence in the ...

but the Australian opals are sedimentary in nature. They are stronger and more expensive.” Australian opal prices reflect their strength, but at Zerzghi’s table, a shopper can score a good ...

There are valuable opportunities on the horizon for the opal industry. ERIK MADSEN says that planning for tomorrow should begin today.