Australia begins more than million years ago when the deserts of central Australia were a great inland sea, with silica-laden sediment deposited around its shoreline. After the sea receded and disappeared to become the great Artesian basin, weathering 30 million years ago released a lot of the silica into a solution which filled cracks in the rocks, layers in clay, and even some fossils. Some of the silica became precious opal. Opal is one of the few gemstones that is sedimentary in origin. The water in opal is a remnant of that ancient sea.
All black opals come exclusively from Australia.
Mystical Properties Opal is used to see possibilities. Some people think the opal is bad luck when worn if it is not your birthstone. This is not true. The story was started by Sir Walter Scott in his novel Anne of Gierstein , in which the heroine of the novel has her life force caught in the beautiful opal she wears and she dies when the fire in the opal is extinguished. In ancient times opal was accepted as a symbol of faithfulness and confidence.