metamorphic
Tiger's Eye
Silica (Quartz) pseudomorph after Crocidolite (SiO2)
Hardness: 6.5-7 Mohs; Color: Golden yellow to deep brown; Luster: Silky; Crystal structure: Trigonal (fibrous texture); Cleavage: None; Specific Gravity: 2.64-2.71.
- Hardness
- 6
- Color
- Golden yellow to deep brown
- Luster
- Silky
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Physical properties
Hardness: 6.5-7 Mohs; Color: Golden yellow to deep brown; Luster: Silky; Crystal structure: Trigonal (fibrous texture); Cleavage: None; Specific Gravity: 2.64-2.71.
Formation & geological history
Formed when quartz replaces fibrous crocidolite (blue asbestos) via a pseudomorphous process, retaining the original fibrous structure. Most deposits are Precambrian in age (over 2 billion years old).
Uses & applications
Primarily used as a gemstone for jewelry (beads, cabochons), ornamental carvings, and talismans in metaphysical practices.
Geological facts
Exhibits a optical effect known as chatoyancy (cat's eye effect), caused by the reflection of light off the parallel mineral fibers. Historically believed by Roman soldiers to provide protection in battle.
Field identification & locations
Identify in the field by its distinct golden-brown banding and chatoyant shimmer when rotated under light. Common locations include South Africa (Northern Cape), Australia, Myanmar, and Namibia. Collectors should look for sharp color contrast and 'flash'.
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