10/18/2018
What makes the beautiful colors of the opal?Water!
Opals are found in sandstone as small sized patches of fused silicon, or "glass". Opal occurs when water is trapped in the sandstone and under heat and pressure and seals in the water so that the colors of the spectrum shines so vividly. When opal is first located it must be kept in water to maintain the colors but once it is polished, the colors are permanently sealed.
Opal mining is dangerous, sandstone tunnels are chipped out ten to twenty feet below the surface in very unstable sandstone that can cave in very easily and the weight is fatal. The miner chips ahead of his crawling and continues until he hears the sound of breaking glass and that signifies opal is found. The opal is usually a small cluster or grapefruit size patch that he carefully extracts and places immediately in water. Then he gradually backs out and hopes to climb out of his tunnel. Point of note: the fiery black opals are from "Lightning Ridge" Australia.