white opal

White opal is a type of opal with a predominantly light-colored body. Opal itself is a silica mineral, a submicrocrystalline variety of cristobalite, widely used as a gemstone. While fundamentally colorless, opal typically contains impurities that give it various body colors, such as yellow and red from iron oxides, or black from manganese oxides and organic carbon. The milky appearance of many white and gray opals is due to numerous tiny gas-filled cavities. Precious opals are translucent to transparent and display a play of colors that flash and change as the stone is viewed from different angles, caused by the interference of light. The finest gem opals come from Australia, with other notable sources including Japan, Mexico, Honduras, India, New Zealand, and the United States.12