gemstone

Tumbled tiger’s-eye

Quartz variety, SiO₂, with crocidolite-derived fibrous inclusions

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; golden-brown to dark brown, vitreous to silky luster, and chatoyancy (cat’s-eye band) caused by aligned fibers. Massive microcrystalline quartz; no visible cleavage; specific gravity about 2.64–2.71.

Identified August 23, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when blue asbestos-like crocidolite fibers are pseudomorphed and replaced by quartz during low-grade metamorphic alteration. Most commercial material formed in Precambrian rocks, especially in the Northern Cape of South Africa.

Uses & applications

Commonly cut into cabochons, beads, carvings, and tumbled stones for jewelry and ornamental objects; generally an affordable gemstone.

Geological facts

Its shifting luminous stripe is strongest when the stone is smoothly polished and viewed under a focused light. Red “bull’s-eye” and blue “hawk’s-eye” are related quartz varieties.

Field identification & locations

Identify it by the sharp moving golden band, brown-gold color, and glassy polish; rotate it under a single light source. Major sources include South Africa, Australia, India, Brazil, and Thailand.