The opal has been cloaked in magic and mystery for centuries. It is set apart from other gemstones because of its characteristic appearance and vibrant colors, which change and flash as you turn the gem in your hand. No two opals are alike. The word 'opal' comes from the Greek word opallos, meaning "to see changes of color", although the Romans are said to have based their name opalus on the Sanskrit word for precious stone, upala. Opal is classified as a precious gemstone. It is a formation of non-crystalline silica gel. Millions of years ago, this silica gel seeped into crevices and cracks of the earth's sedimentary strata. Through eons of time and through nature's heating and molding processes, the gel hardened and can today be found in the form of brilliant opal.