I traded opals for a while, but my supply was boulder opals from around Quilpie in Queensland. Not underground like Coober Pedy and White Cliffs, but still not

I traded opals for a while, but my supply was boulder opals from around Quilpie in Queensland. Not underground like Coober Pedy and White Cliffs, but still not a whole lot there![1] One of the best introductory books about opals is Opal Identification & Value by Paul B. Downing. It's a few years old now (latest version 2002, first published 1992), but really does cover all the basics of different types and their value very well. [1] http://www.opalsdownunder.com.au/learn-about-opals/intermediate/queensland-opal-mining-fields http://www.opalsdownunder.com.au/learn-about-opals/intermedi...