Opal is the birthstone of the October born. The special characteristic of this gem is its opalescence, a rainbow like iridescence which changes with the angle of Observation. More than 90 per cent of opal produce is found in Australia. There are four major opal  fields; Quilpie in Queensland known for its boulder opal, Lightning Ridge in New South Wales for its famous black opals, the costly brilliant red on a black background, and Coober Pedy and Mintabie in South Australia for the milky white opals.  Mexico prides itself with its orange fire opal.

Always make sure you purchase a solid opal as there are cheap doublets and  triplets, consisting of other mineral stones pasted together with a thin veneer of opal to lure tourists .