The three varieties of quartz described here all have a fibrous structure, with inclusions of crocidolite (blue asbestos) that cause a "cat's-eye" effect known as chiromancy. This effect is best seen when the stones are cut en cabochon. Each stone displays different colors according to the exact nature of the inclusions. The grayish yellow, semi- Translucent appearance of quartz cat s-eye is due to inclusions of crocidolite "asbestos" and. less commonly, hornblende. It has a silky luster. Tiger's-eye is black; with iron oxide staining that gives yellow and golden brown stripes. Hawk's-eye forms when crocidolite changes to quartz, but the blue-grey or blue-green color of the original remains.

Quartz cat's-eye comes from Sri Lanka. India and Brazil. The most important source of tiger's-eye is in South Africa, where it is found in thick slabs, together with the less common hawk's-eye. Chatoyant quartz is also found in Australia and the USA.

Chatoyant quartz is always called quartz cat's-eye to avoid confusion with other chatoyant gems, particularly chrysobery. Hawk's-eye cigarette Box In this attractive ornament, made of polished slices of blue hawk's-eye. The wavy, fibrous nature of the original asbestos can be clearly seen. Partial oxidation has created a few yellow waves.