Product Type: moonStone garnet weight: : Transparent only Color: White origin: India shape: Oval Cabochon Size:mm treatment: untreated Moonstone Gemstone Information Moonstone - History and Introduction Moonstone is the most well-known gemstone variety of orthoclase feldspar, a potassium aluminum silicate. It is a transparent to opaque oligoclase, a variety of plagioclase albite and sheet mica. Moonstone is known to exhibit a distinct sheen under certain lighting conditions, and it is the sheen which renders moonstone one of the most remarkable gemstones available today. In fact, its name is owed to the almost magical, bluish white shimmer it exhibits, which closely resembles that of the moon. Gemologists refer to the shimmering phenomena as 'adularescence'. The optical effect of adularescence is a result of moonstone's unique structural pattern. Tiny inclusions of albite, a sodium aluminum silicate are intermixed with host rock layers of orthoclase, a potassium aluminum silicate. The alternating layers of different feldspars form a lamellar (scaly) structure which causes the interference of light as it enters the stone. Thin layers of alternating silicates tend to refract more attractive and colorful sheens, whereas thick layers of silicates produce less attractive, white to colorless sheens. As light enters the stone, it is refracted and scattered, producing an extremely unique and attractive play of both color and light. With moonstone, the aura of light actually appears to glow from deep within the surface of the stone.