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.

Fire opals are translucent and contain shades ... are fueling the rise in popularity of this unusual stone. The Most Expensive Black Diamond in the World It's difficult to ascertain what the ...

In a fossil-rich pocket of northern New South Wales, two pioneering palaeontologists have spent decades digging up rare ...

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.

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.

The most valuable banknotes are nearly all worth less than $100,000, according to Banknote World. In contrast, the most valuable coins can command $3 million or more. If you have a rare $1 bill ...

Most of these are accounted for, but the good news is that some valuable coins are still out there if you are looking to get your hands on some precious metals. You could potentially find these in ...

"One of the most valuable opals in the world named 'Olympic Australis' weighs 17,000 carats and is said to be valued at approximately $2.5 million," he adds. "The good news is that affordable ...

Nor did its authors give any sign of recognizing that the ideas in the Manifesto might eventually help to generate the most valuable and fastest growing firms in the world (as shown below in ...

A house that sold for $480,000 tops the list of the most expensive residential real estate sales in North Ridgeville in the ...