Opals
by darthmilmo
Defining an opal takes you through a journey of central Australia's geological past. Basically, billions of years ago, there used to be an inland ocean residing in Central Australia. Over the years, the ocean accumulated sediments, such as sand, dead animals and the like. Eventually, as Australia kept shifting, the ocean receded. Before the ocean receded, the silica in the sand made its way down into the remaining gaps of the compressed sandstone. Some took the shape of the dead animal others just took whatever gap they could find. After millions of years, the silica slowly converted into Opals. Australia is the only place on earth where fossilized opals abound. I've seen a beautiful specimen in the South Australia Museum at Adelaide. It also counts with some of the purest and more colorful opals. The more colors are given off by the opal, the more it is worth. Unlike the early days,...