"Mandarin garnet" specimens are the most in demand and the most expensive. Spessartine gem quality stones are rarely larger ...

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 ...

Most expensive opal: $1 million Bottom Line: Opal The opal, also known as the October birthstone, can be anything from utterly ordinary to downright jaw-dropping.

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 ...

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.

An extensive and valuable opal collection considered the premier opal collection in the 1980s is up for auction and could be lost for the people of Australia. BRISBANE, QUEENSLAND, AUSTRALIA, June ...