Front and back covers scuffed, with slight crease in front cover. Well illustrated publication on the opal mines of the area around Cunnamulla in Queensland, Australia. Known for the Yowah, Koroit and East Gate opal fields, this area produces beautiful boulder opal found in Cretaceous ancient sandstones in an ironstone matrix. Describes the types of opal found, mining methods, history and miners of the opal fields. Written by the prolific opal author Len Cram. This publication includes 4 beautiful tear-out postcards (attached) featuring beautiful opal gemstones, and a map of the opal District. 32 pages.