metamorphic
Tumbled tiger’s eye
Tiger’s-eye quartz, SiO₂ with crocidolite pseudomorphs
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; golden-brown to dark brown, vitreous to silky luster, opaque, with chatoyant bands caused by aligned fibrous inclusions. Quartz has a trigonal crystal structure, but the tumbled piece has no visible cleavage.
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Physical properties
Hardness 6.5–7 Mohs; golden-brown to dark brown, vitreous to silky luster, opaque, with chatoyant bands caused by aligned fibrous inclusions. Quartz has a trigonal crystal structure, but the tumbled piece has no visible cleavage.
Formation & geological history
Forms when fibrous blue asbestos (crocidolite) is replaced by quartz during hydrothermal alteration, preserving the fibers and producing chatoyancy; commonly associated with Precambrian rocks of South Africa and Western Australia.
Uses & applications
Used for cabochons, beads, carvings, and inexpensive ornamental objects; not generally used as a major construction stone.
Geological facts
Its moving, cat’s-eye-like band is called chatoyancy and is strongest when the stone is cut parallel to the fibers. Golden tiger’s-eye commonly develops from altered hawk’s-eye.
Field identification & locations
Identify it by its polished brown-gold color, fibrous silky sheen, and bright band that moves across the surface when rotated under a point light. Common sources include South Africa, Australia, India, and Thailand.
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