metamorphic
Likely tiger’s-eye rough
Quartz-rich fibrous rock, chiefly SiO₂ with iron-oxide-stained crocidolite (riebeckite) fibers
AI-generated identification · may be incorrectGolden-brown, fibrous and silky with possible chatoyancy; quartz hardness 7 Mohs, no obvious cleavage, and typically a compact fibrous texture. The photo alone cannot confirm the identification; the specimen appears rough and fractured.
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Physical properties
Golden-brown, fibrous and silky with possible chatoyancy; quartz hardness 7 Mohs, no obvious cleavage, and typically a compact fibrous texture. The photo alone cannot confirm the identification; the specimen appears rough and fractured.
Formation & geological history
Forms when silica replaces crocidolite fibers, commonly during low-grade alteration of iron-rich rocks; deposits are notably associated with South Africa and Western Australia. The rock’s formation age depends on its deposit.
Uses & applications
Polished cabochons, beads, carvings, and collectibles; not generally used as a major construction material.
Geological facts
Its moving, cat-eye-like band of reflected light is caused by aligned fibers and is strongest in well-cut, polished pieces.
Field identification & locations
Look for parallel golden-brown fibers and a shifting silky sheen when rotated in light; confirm with a fresh surface or gemological testing, since this rough piece shows little clear chatoyancy.
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