Opal is formed from a solution of silicon dioxide and water. As water runs down through the earth, it picks up silica from sandstone, and carries this silica-rich solution into cracks and voids, caused by natural faults or decomposing fossils. As the water evaporates, it leaves behind a silica deposit. This cycle repeats over millions of years and eventually Opal is formed.
Australia has three major varieties of natural sediment Precious Opal – Black Opals from Lightning Ridge in New South Wales, White Opals from South Australia, and Queensland Boulder Opal (near our flagship store).
The many variations in the types of Opal depends on several factors. In particular, the climate’s wet and dry periods create a rising or falling water table which concentrates any silica in solution.
Check out our award winning film, "Boulder Opal Country" to discover more about Queensland Boulder Opal and the small nearby town of "Winton".
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