Five of Australia's states have official emblems related to geology, and the country also has a national gemstone emblem: opal
. Australia supplies the great majority of the world's gem opal. The stone is painstakingly harvested from small mines in opal fields scattered around the country's deeply weathered, desert interior in the states of New South Wales, Queensland and South Australia. Opal was discovered in Australia in 1849, and the industry mushroomed starting in the 1890s.