Rock Identifier
Polished tiger’s-eye (Quartz (SiO₂), chatoyant fibrous variety; commonly golden-brown tiger’s-eye) — mineral
mineral

Polished tiger’s-eye

Quartz (SiO₂), chatoyant fibrous variety; commonly golden-brown tiger’s-eye

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; brown to golden bands, vitreous-to-silky luster, opaque, with chatoyancy (cat’s-eye effect) from aligned fibers. Quartz is trigonal and has no cleavage; specific gravity is about 2.65.

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Physical properties

Hardness 6.5–7 Mohs; brown to golden bands, vitreous-to-silky luster, opaque, with chatoyancy (cat’s-eye effect) from aligned fibers. Quartz is trigonal and has no cleavage; specific gravity is about 2.65.

Formation & geological history

Forms when crocidolite asbestos fibers are pseudomorphed and silicified by quartz during hydrothermal alteration, commonly in Precambrian iron-rich rocks. Most commercial material comes from South Africa and Western Australia.

Uses & applications

Used for cabochons, beads, carvings, paperweights, and inexpensive ornamental jewelry; its durability suits polished pieces but not high-impact applications.

Geological facts

The moving bright band is caused by reflected light from parallel fibrous inclusions, especially when the stone is polished parallel to the fibers. Blue, red, and golden varieties are called hawk’s-eye, bull’s-eye, and tiger’s-eye, respectively.

Field identification & locations

Identify it by its silky, shifting band of reflected light, brown-gold coloration, and lack of distinct crystal faces; dyed or heat-treated pieces may show unusually vivid colors. Common localities include South Africa, Australia, India, Brazil, and Namibia.