As you might already know Australia currently produces about 95 per cent of the world’s precious opal. So why does no other country on Earth have such an abundance of Opal? Lets go back some million years to find out. If we look at the widely scattered opal fields throughout central Australia the sedimentary opal deposits occur along generally flat-lying areas within 30 metres of the earth’s surface. They came to occur over a 100 million year period with a unique series of geological events which were as follows: Sometime between 91 - 122 million years ago central Australia was covered by ...