mineral

Tumbled tiger’s-eye

Quartz variety, mainly fibrous quartz pseudomorph after crocidolite; SiO₂

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; golden-brown to reddish-brown silky chatoyant bands, vitreous-to-silky luster, trigonal quartz structure, and no prominent cleavage. The reflected band of light (“chatoyancy”) is its key feature.

Identified September 13, 2026More mineral →

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Physical properties

Formation & geological history

Forms when crocidolite asbestos fibers are replaced by quartz, commonly during weathering and alteration of iron-rich rocks; iron oxidation creates the gold-brown color. Major deposits are Precambrian in age, especially in South Africa and Western Australia.

Uses & applications

Commonly cut into cabochons, beads, carvings, and ornamental stones; also sold as an inexpensive collector and metaphysical specimen.

Geological facts

Its cat’s-eye effect results from aligned internal fibers reflecting light. Blue crocidolite-rich material is called hawk’s-eye; red-brown varieties may be called bull’s-eye.

Field identification & locations

Identify it by its glassy golden bands and moving silky stripe when rotated under directional light; it should scratch ordinary glass but not quartz. Common sources include South Africa, Australia, India, Brazil, and the United States.