Australian opal can be found in several states. Discover the magic of colourful gemstones found in the Australian Outback.
Look at an opal stone from different angles - it changes it colours. The beauty of opals, the play of colours, has fascinated people for centuries.
Do you have questions about Australian opal?
In simple terms, opal is a mix of silica and water. Scientifically, opal is amorphous silica (SiO2.nH2O) which is solidified from liquid silica.
As you can imagine, the synthesis of opal was an ancient process. The building process started about 15 - 30 million years ago. Silica gel seeped through sedimentary layers until it was stopped by a clay level. Australian opal therefore is called sedimentary mineraloid. Over million of years, the liquid Silica gel hardened to form the opal deposit of the artesian basin, the ancient underground water reservoir of the eastern Outback.
Australia's precious opals contain around 5 -6 % water.
Generally, opal comes in two forms
Want to see what can be done with precious opal?
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Common opal and potch has a similar structure than precious opal, but the arrangement of the silica spheres is slightly different. That's why these stones don't have the play of colours.
Sometimes the opal layer in a rock is so thin there is no way to cut a solid stone. In this case the layer is glued to a piece of potch or obsidian. This is called a doublet.
To protect the doublet a layer of transparent material like quartz is added sometimes. The result is called a triplet.
Look at the video to see that it is not easy to turn a piece of raw opal into a gem.
Opal is mined in South Australia, Queensland and New South Wales. A trip to the mining fields in whatever state is a wonderful journey into the Australian Outback.
April to late September is the best time for a trip. Most of these unique towns can be reached by sealed roads, although it is often a fair drive to get there. Summer is usually too hot to enjoy a visit. That's why residents in Coober Pedy and White Cliffs often live in "dugouts" underground.
The Australian climate page (in the link section below) gives you an idea about when to visit the Australian Outback.