Cat’s Eye is not a specific mineral, but rather a special affect that happens to many different minerals. A Cat’s Eye is a mineral which when cut and polished, reveals a strong, narrow light which moves from side to side as the mineral is shifted. This line of light resembles the slit pupil in the eyes of cat’s, hence the name. The proper scientific name for this line of light is chatoyancy. Cat’s Eye may sometimes be found on Apatite, Beryl, Chrysoberyl, Moonstone, Opal, Quartz, Ruby, Sapphire and many other stones. But unless otherwise labeled, most of the “Cat’s Eye” sold on the market is Chrysoberyl.
Chrysoberyl Cat’s Eye was the “original” Cat’s Eye. The first documented reference to chatoyancy was in 1789 by the German geologist and gifted teacher, Abraham Gottlob Werner (1749-1817). At the time, Chrysoberyl was called Chrysolite, which is an ancient gem name given to many different kind of green or golden crystals. When Cat’s Eye is found on Quartz, the name typically refers to a grayish stone with a white chatoyant band. But when the colors are more striking, such as a bright blue, golden-brown or vivid red color, the stone is elevated from a “Cat’s eye” to become a “Tigers eye.”