Gemstones of Australia
Opal is the most Australian of gems. This continent has mined most of the world's production and the world's finest specimens for more than a century. But Australia has much more to offer the gem collector than just opal.
Australia is also the world's largest producer of diamonds: the Argyle mine produces 30 to 40 million carats a year.
Large in number, Argyle's diamonds are generally small in size: in fact, the automated plant built to process the rough diamonds would crush a large stone.
Because of the mine’s unique geology, in addition to white diamonds Argyle produces champagne, cognac and other brown shades. It also produces fabulous, but unfortunately rather rare, pink diamonds.
Australia is also the world’s most important source for South Sea cultured pearls. The pearl farms in the warm water bays off Australia’s northern coast near Broome and Darwin are known for these lustrous and valuable pearls, which are grown in the jumbo Pinctada Maxima oyster. South Sea pearls are the giants of the pearl world, ranging from 8mm up to jawbreaker-like 22mm sizes. South Sea cultured pearls range in color from silver to white, cream, and golden tones.
Australian sapphires are mined in both new South Wales and Queensland. Between 1960 and 1985, Australia was the source of 60 percent of the world’s sapphire. Unfortunately most of it was lower quality. Today the quantity is smaller but the quality is much better. Most Australian sapphire is a deep blue but yellow and greens are also found. The best Australian sapphire, Royal Kings Plain Sapphire, is a rich royal blue.
Chrysoprase, the bright green translucent quartz, is found both in Queensland and Western Australia. Again, this continent is the world’s most important supplier.
But opal is Australia’s signature gem. The volume and variety is staggering. Australia produces white opal, bolder opal, crystal opal, black opal, and even entire fossils made out of opal. At its best, opal contains all the colors of the rainbow in flashing and moving spectral hues known as play of color. Opal’s play of color is created by internal diffraction: tiny silica spheres in grids break up the light into spectral colors, much like the tiny grooves on CDs, that shimmer with iridescence. These colors are the most visible in opal with dark body color, which is why these gems, known as black opal, are the most valuable.
Learn more about these Australian gems in our Gem Fact Files:
Royal Kings Plain Sapphire