The major outcrops of opal an ancient inland sea (known as the Eromanga Sea). The important mining areas in Australian opal production over the last century have been White Cliffs, the Queensland fields, Lightning Ridge, Grawin, Glengarry, Coober Pedy, Andamooka, Mintabie and Lambina. White Cliffs Commercial mining commenced in the late 1880s at the White…
DetailsPrecious Opal is composed of minute uniform spheres of silica, which are arranged together in orderly three-dimensional grid. The spaces between these spheres contain silica in solution. However, in common opal, where there is no play of colour the spheres are varying sizes and are not uniformly stacked. White light passes through the transparent sphere…
DetailsHighly recommend Cosmopolitan Jewellers. I purchased several pieces of opal and pearl jewelry from overseas using the internet and email to view and select the jewelry. Jenny has been extremely helpful with videos and prompt response to all my questions. The transaction and shipment went smoothly. The jewelry is the highest quality and exceeded my…
DetailsOpal 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…
DetailsThroughout 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…
DetailsOpal 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…
DetailsThere 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…
DetailsAustralian Opal is found in sedimentary rocks aged 115-100 million years. The majority of Opal is quite hard and will scratch glass. However, there are a few areas that some fields that produce unstable material with a higher water content, which can crack or craze. It is important to buy your opal from reputable jewellers…
DetailsThere 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…
DetailsBy 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…
DetailsAustralia’s Great Artesian Basin (GSB) 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 mainly found in the opal fields of South Australia, Boulder Opal…
DetailsOpal 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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