Koroit Opal is a type of Boulder Opal, named after the area it is mined from, the Koroit opal field, in Paroo Shire in South West Queensland, not far from Yowah which produce a similar Opal. Koroit Opal has a distinctive and unique pattern which is why we have categorised it aside from the other Opal Boulders. This opal is also known for its hardness, diversity and value for money and is in high demand locally and overseas, noticeably in Germany and the USA.
Like Boulder Opals, Koroit Opals are characterised by being a natural combination of solid opal and ironstone or in some cases fossilised wood. The opal formed within the cracks of the ironstone boulder, which when split shows a shiny and deep coloured opal faces against the dark brown stone.
Yowah nuts are mini boulders of 5mm to 20cm which host an opal. They are specific to the Yowah region, hence the name. Other host boulders from Queensland can vary in size greatly, and even reach meters, meaning that Boulder Opals are generally a cut from the host, making Yowah nuts a rare gemstone for its entirety.
Patterns and types can be related to the opal field they are mined from. To help with selective viewing, we also created a region filter to select areas like Yowah when viewing all products; other smaller opal fields may be mentioned in the stone detailed description along with patterns and colours.