Opalized bivalve found in Coober Pedy. Photo by James St. John. Licensed under CC By 2.0.
ABC's "The Science Show" has a fascinating segment about the opals of Australia. 90% of the opals on Earth come from Australia. Many come from the cities of Lightning Ridge and Coober Pedy. They formed about 120 million years ago when the conditions were perfect for opal creation. There's also a discussion about the process of opal formation. Do you have opal fever yet?!?
It was the clue that made all the difference to the professor of geology at the University of Sydney. The quandary was about the near unique presence of opals in Australia. We knew the basic ingredient is volcanic, but what transforms the black basalt into shining, multi-coloured stones? Jonica Newby visits the opal mining town of Lightning Ridge in western NSW and meets the geology professor obsessed about opals from childhood who made it his quest to discover how opals are formed.
