5.55cts Queensland Boulder Opal Stone Dimensions (mm) 22 x 9 x 3mm Weight (cts) 5.55 Type Polished Shape Freeform Opal Type: Australian Boulder Opal Origin: Winton Region Treated/Untreated: Untreated Colour: Multi - Colour Pattern: Mixed Flashes Accuracy of picture: Accurate Base of opal: Solid Native Ironstone Cabochon: Low Comments: A free form shape Australian Boulder Opal stone with mixed flashes of multi-colour on a ironstone base. Queensland Boulder Opal Gem Cabochon – Freeform Discover the natural beauty of this **Queensland Boulder Opal Gem Cabochon**, expertly polished to a high, lustrous shine to showcase its unique character and natural opal colours. Its freeform shape celebrates the individuality of the stone, making it a beautiful addition to any gemstone collection or an ideal choice for jewellery making. Queensland, Australia, is world-renowned for its beautiful Boulder Opals, particularly from the outback regions of Quilpie, Winton, and Koroit. These remarkable gemstones formed approximately 100 million years ago during the Cretaceous Period, when silica-rich solutions gradually filled cracks, cavities and spaces within ancient ironstone boulders. Over millions of years, the silica hardened into precious opal, creating distinctive flashes of colour against the natural ironstone host rock. Each Queensland Boulder Opal is unique, reflecting the remarkable geological history of the Australian outback. With its natural character, freeform shape and high-gloss polish, this cabochon is a wonderful example of Australia's treasured opal heritage.