Potch Opal

Besides the gemstone varieties of opal that show a play of color, there are other kinds of opal ( common opal ) such as the milk opal, resin opal, which is honey-yellow with a resinous luster, wood opal, which is caused by the replacement of the organic material in wood with opal which can sometimes be prescious wood replacement, menilite, which is brown or grey, hyalite, a colorless glass-clear opal sometimes called Muller's Glass, geyserite, also called siliceous sinter, deposited around hot springs or geysers and diatomite or diatomaceous earth, the accumulations of diatom shells or tests. Most commonly in the Australian opal fields we find cloudy potch from white in all shades of grey to black and caramel potch.