metamorphic
Polished tiger’s-eye
Chatoyant quartz, primarily SiO₂, with iron-oxide staining
AI-generated identification · may be incorrectMohs hardness 6.5–7; golden-brown to reddish-brown silky bands, vitreous-to-waxy luster, and fibrous quartz structure producing chatoyancy. No obvious cleavage; conchoidal fracture; specific gravity about 2.6–2.7.
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Physical properties
Mohs hardness 6.5–7; golden-brown to reddish-brown silky bands, vitreous-to-waxy luster, and fibrous quartz structure producing chatoyancy. No obvious cleavage; conchoidal fracture; specific gravity about 2.6–2.7.
Formation & geological history
Formed when crocidolite asbestos fibers in quartz-rich rock were pseudomorphed and replaced by quartz, with iron oxidation creating golden-brown color. It is commonly associated with Precambrian metamorphic rocks, especially in southern Africa.
Uses & applications
Used for cabochons, beads, carvings, polished stones, and ornamental objects; occasionally used as a decorative building stone. Its value is primarily lapidary and collectible.
Geological facts
The moving cat’s-eye sheen is strongest when the stone is cut parallel to its fibrous bands. Red-brown material is often called bull’s-eye or red tiger’s-eye and may reflect natural oxidation or heat treatment.
Field identification & locations
Identify it by its directional, silky light band that shifts as the stone moves, plus hardness sufficient to scratch glass. Major sources include South Africa, Western Australia, India, Brazil, and Namibia.
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