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 Expensive Fire Opal in the World. The Fire of Australia is known as the finest uncut opal in existence and is worth ...

The Gold Coast dad has now revealed the incredibly rare and lucrative discovery made inside one of the rocks — which recently ...

The most valuable black opal features bright red stone against a very black base. In the '80s and '90s, gem-quality brown diamonds were worth about $1,500 per carat, but now many sell for up to ...

Meet the "Virgin Rainbow" – perhaps the finest and certainly the most expensive opal on record. It literally glows in the dark. In fact, as it gets darker around the opal, the opal appears ever ...

In fact, the world's most valuable black opal – the cruise liner-sounding 'Aurora Australis' – was found in 1938 at Lightning Ridge in New South Wales.

The 'Virgin Rainbow' is one of the world's rarest and most expensive opals. This extremely rare opal exhibits incredible fluorescence with a rainbow of different colors that make opal so ...

The largest and most valuable single piece of rough gem opal is the Olympic Australis (not pictured), a 3.4 kilogram, 17,000 carat stone estimated to be worth about $1.9 million.