 Tiger's Eye TIGER'S EYE QUARTZ, ALSO SPELLED tiger-eye, is a semiprecious variety of quartz exhibiting chatoyancy, a vertical luminescent band like that of a cat's eye. Unlike cat's-eye quartz, tiger's eye is formed when parallel veins of crocidolite (blue asbestos) fibers are first altered to iron oxides and then replaced by silica. As a result, it is more opaque and has a rich yellow to brown color. When cut en cabochon, the gem has a fine luster. |