metamorphic
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)
Hardness: 7 Mohs; Color: golden brown to yellow; Luster: silky; Structure: trigonal/fibrous; Features chatoyancy (cat's eye effect); Specific gravity: 2.64-2.71.
- Hardness
- 7 Mohs
- Color
- golden brown to yellow
- Luster
- silky
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Physical properties
Hardness: 7 Mohs; Color: golden brown to yellow; Luster: silky; Structure: trigonal/fibrous; Features chatoyancy (cat's eye effect); Specific gravity: 2.64-2.71.
Formation & geological history
Formed when quartz replaces fibrous crocidolite (blue asbestos fibers) through a process of pseudomorphism, where the original mineral shape is preserved while the chemistry changes. Primarily occurs in iron formations.
Uses & applications
Popular for jewelry (cabochons, beads), decorative carvings, spiritual/metaphysical collecting, and lapidary arts.
Geological facts
Tiger's Eye is a classic example of chatoyancy. It is a 'pseudomorph', meaning 'false form', as it looks like asbestos but is actually quartz. If it is heat-treated, it turns red (Red Tiger's Eye).
Field identification & locations
Identify by its distinct golden-yellow bands and the shifting light effect (chatoyancy) when rotated. Commonly found in South Africa, Australia, and Namibia. Best identified in the field by its fibrous appearance and high hardness.
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