What is a Coober Pedy opal ?

A Coober Pedy opal is a precious opal that has been mined in or around Coober Pedy, an opal mining field in South Australia, Australia.
Coober Pedy produces over 90% of all precious opal mined in the world (mostly white opal but also beautiful light and crystal opal). It is the main source of opal used to make opal doublets and opal triplets.
When cut and polished, a solid Coober Pedy opal is by world standards, a "Natural opal, Type 1".