Glengarry Opal Field About 45 km from Lightning Ridge there is another extensive opal mining area where mining is still being carried out today. Fields have been established at Glengarry, Grawin, Sheepyard Flat, Carters Rush and Mulga Rush. These fields are all relatively close together and...

Andamooka Rainbow Matrix Opal is fast becoming popular with those who can't afford a "Real Opal". Originally it was called "concrete" because that was what it looked like although you could see small specks of opal in amongst the concrete like grains. It is a porous quartzite host rock in which opal has been deposited amongst the quartz grains. In its raw state you can hardly see the opal and for this reason the early miners discarded it as valueless. If you hunt around the mullock heaps or even on the roadsides in Andamooka you still have a chance of picking up  a piece. A photo of a typical piece of concrete is shown below.