Few realize that the world’s most famous black fire opal – the official Nevada State Gem – was discovered in Nevada’s remote Virgin Valley in 1918. Col. W.A. Roebling, a civil engineer who helped ...

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 ...

It's been more than a decade to market for one of the world's most impressive opals, which will be on sale this weekend at an upscale jewelry event in Las Vegas. The minimum asking price: $3 million.

The opening scene shows the black opal's discovery in a dodgy Ethiopian mine – this, we learn, is a gem whose provenance is as ethically questionable as Ratner, the man who acquires it.