New South Wales
Opal is found in many parts of Australia but it is the elusive Black Opal that has made Lightning Ridge famous. This rare gem is an appropriate symbol of the town as the exact nature of Lightning Ridge and its people is as mysterious as the stone itself.
Opal is non-crystalline silica, similar to quartz, but is not a mineral. Its internal structure enables unique diffraction of light to produce white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Opal is formed from a solution of silica (very fine sand-like particles) and water. In some sandstone outback regions, water passes though the sandstone to form a silica-rich solution that flows to voids formed from decomposed fossils and as the water evaporates, a silica deposit is left. This is repeated over vast periods and from it, an Opal is formed.