BOULDER OPAL POLISHED YOWAH
A Boulder Opal Polished Yowah Gem Stone. A great splash of rainbow coloured Opal to show off to your friends. This beauty has been cut by a local opal cutter and shows 3 dimensional form and contours. This Opal would suit jewellery in pendant or ring form. The cut is free form and the opal is solid.
1.2cm x 3.1cm x 0.57cm, 23.09ct.
Opal: SiO2 · nH2O Hydrated Silicon Dioxide.
Boulder Opal is a variety of Precious Opal found in Queensland, Australia, as cracks or coatings in and around ironstone/sandstone boulders. Opal has been a popular gem for many centuries and has a very interesting structure. The name opal probably is derived from the Sanskrit name for precious stone- upala. Opal is considered a mineraloid because this structure is not truly crystalline. The chemistry of Opal is primarily SiO2 and varying amounts of water. The amount of water varies from 5 -10% and greater. This water can help geologists determine the temperature of the host rock at the time the opal formed.