Why is opal only found in Australia?

Why is opal only found in Australia?

Much of the world’s precious opal is mined in the harsh outback of Australia, where a unique combination of geological conditions permitted the formation of opal near the margins of an ancient inland sea. Australia is regarded as the world’s leading source of opal and of the world’s finest opal.

What rock is opal found in?

Opal is found as two types: volcanic opal which infills vesicles and cracks in igneous rocks, and the more familiar sedimentary or sandstone type which is found in Australia’s main fields. Most deposits in other countries are volcanic opal, much of which is prone to crazing.

Where can opal be found naturally?

More than 90% of the world’s precious opals come from Australia, and the rest can be found in other parts of the world such as Mexico, Brazil, Indonesia, Czech Republic, Ethiopia and USA. Opals from Mexico (called “Mexican Opal”) has more water and is transparent or extremely translucent.

Where is opal most likely formed?

While volcanic-hosted and other types of precious opal are found in Australia, virtually all economic production comes from sediment-hosted deposits associated with the Great Australian Basin.