Where does Opal Come From?

See My Photos of this trip here

AUSTRALIA, the lucky country, was blessed when nature chose her as the host for the world's richest reserves of the most beautiful gem on Earth, Opal. With the exception of a few isolated pockets around the coastal regions, all of Australia's commercial opal is found in the inland desert areas. It occurs west of the Great Dividing Range over an area of approximately 500,000 square kilometers stretching well into the state of Western Australia. Most of the well-known reserves are located in South Australia, New South Wales and Queensland.

Except for a very small percentage of volcanic opal, Australia's commercial opal is found in cretaceous (about 140 million years ago) sedimentary rock formations. This is true for the fields in NSW and South Australia. However, in Queensland the opal can often be much younger coming in the Eocene or tertiary age. Geologically, this is recognized as being the period from about 65 million years ago. So the Queensland opal geology is different to the others in Australia. It is different because of the type of parent material in which it was formed. The very beautiful Queensland variety is generally known as Boulder Opal.

More to come.....