The home-grown gems that have become Australian icons.
Located in the wildly beautiful and remote Kimberely area of Western Australia, Rio Tinto’s Argyle Diamond mine produces many of the world’s diamonds with most of them ending up as centrepieces in fine jewellery. It is the only known significant source of pink diamonds, producing over 90% of the world’s supply.
Of the small percentage of gem quality diamonds produced by Argyle, none are more famous or prized than the pink diamonds. These pinks are exceptionally rare and fetch exceptionally high prices. To understand just how rare they are consider the number of pink diamonds that the mine produced in 2007. Of the 18 million carats of diamonds that the mine produced in 2007 only 65 carats were of a quality, size and colour to be classified as signature pink.
South Sea Pearls
Their large size, limited culturing area and extended growth period all combine to make South Sea pearls the rarest of all pearl types. Found in colours ranging from optic white to a deep honey gold, these pearls are prized by collectors and designers alike. The lustre of South Sea pearls, whether white or golden, is soft and luxurious. Only a small percentage of South Sea pearls are spherical and as such, full strands of matched pearls are
South Sea pearls are generally much larger than other pearl types and have a unique lustre quality – a soft reflection due to the large aragonite platelets that make up the pearl. They also have the thickest average nacre of all cultured pearls. These factors make South Sea pearls both distinctive and valuable. South Sea pearls have the highest value and command the highest prices of all types of pearls.
Proclaimed as Australia’s most famous gemstone, Opal has long been admired throughout the ages – from ancient Romans to the Aztecs and the Arabs. Staking its position in the world from its first discovery more than 2000 years ago, Opal is the only gemstone in the world whose colour is created by refracted light, gifting it with seven colours of the rainbow. With its flashes of spectral colour and pattern, no two opals are ever alike. Similar to the rainbow colours on a soap bubble, its effect changes with the smallest rotation.
Australia is one of the few places on earth where the unique combination of criteria is needed for Opal to occur. Opal is generally found at depths between 10 to 30 meters below the surface in a layer of claystone or “opal dirt”, immediately below a level of sandstone.
Producing well over 90% of the world’s supply of Opal and approximately 99% of gem quality Opal, major Australian opal fields are located in Lightning Ridge and White Cliffs in New South Wales (Black Opal), Coober Pedy, Andamooka and Mintabie in South Australia (Light Opal) and various locations in Queensland which produce Boulder Opal.
Lightning Ridge Black Opals
Originally known as Wallangulla, Lightning Ridge, just beyond the town of Walgett in northeast New South Wales and about 65km south of the Queensland border, is famed locality for the Black Opal first found here in 1900 by boundary rider Jack Murray.
Black Opal is White Opal stuck to a black rock. The blackness from the black rock comes from seaweed, in particular the manganese contained in seaweed, which gives it its blue-black to dark grey body tone. Fine examples of this variety are the most expensive per carat and rival diamonds in price.