Water in Opal

Opal is a hydrous silica composed of predominantly silicon dioxide and water. The chemical composition of opal Is normally described by the general formula SiO,.nH,O. The formula indicates that opal contains water and the value of ‘n’ is variable so the water content is variable and is known to range widely. Such a simple formula…

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October Birthstone – Opal

Throughout history Opal has been regarded as the stone of good fortune.  Late in the 19th and early in the 20th century, for commercial reasons, there was a proliferation of damaging reports that opal as an unlucky stone. These were based upon a misinterpretation.  In Roman times the gem was carried as a good luck…

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Opal Curiosities

Opal is Australia’s National Gemstone, with each of Australia’s major opal fields having its own distinctive geology, opal types, fossils, landscape, natural and cultural heritage. This panoply of treasures, unique in the world, is the consequence of a freakish combination of geological conditions (Rey 2013). Gemstone laboratories and industry participants, educators and opal enthusiasts look…

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Valuing Australian Opal

There is no governing body which has sent the prices for opal; they are the result of what the international market is prepared to pay in order to obtain the gem. As with any other commodity, opal is subject to the laws of supply and demand. The supply opal is never guaranteed – the lack of…

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Five Virtues of South Sea Pearls

There are five virtues of fine Pearls that define their value; Lustre, Size, Shape, Complexion and Colour. Lustre Lustre is the paramount characteristic of pearl quality that is instantly noticeable. It is not only how light reflects from Pearl’s surface, but also how it seems to glow from within.  Like all virtues, the lustre of…

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Opal and the Dinosaurs

By strange coincidence and only on rare occasions, fossil bones from the Early Cretaceous period (115-100 million years) have been found which have been replaced opal. In exceptional circumstances the opal can exhibit a brilliant play of colour.  Opalised remains from the “Age of the dinosaurs” have been important for understanding past environments and the…

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Where is Opal mined in Australia?

Opal Black Opal, Boulder Opal and White Opal deposits in Australia Australia’s Great Artesian Basin (GAB) hosts widespread deposits of Opal, and continue to be the major source of high-quality gem opal for the international coloured gemstone market. Opal mining in the GAB has produce billions of dollars’ worth of exquisite gems, including light opal…

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Why is Australian Opal so unique?

All of Nature’s splendour seems to be reflected in the manifold opulence of fine opals: fire and lightening, all the colours of the rainbow and the soft shine of far seas. Australia is the classical country of region. Almost 95% of all fine opals come from the dry and remote outback deserts, Australia. The Roman…

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