metamorphic
Tiger's Eye
Pseudomorph of quartz after crocidolite (SiO2 with iron oxide inclusions)
Hardness: 6.5-7.0 (Mohs); Color: Golden to red-brown; Luster: Silky; Crystal structure: Trigonal/Fibrous; Cleavage: None; Specific Gravity: 2.64-2.71.
- Hardness
- 6
- Color
- Golden to red-brown
- Luster
- Silky
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Physical properties
Hardness: 6.5-7.0 (Mohs); Color: Golden to red-brown; Luster: Silky; Crystal structure: Trigonal/Fibrous; Cleavage: None; Specific Gravity: 2.64-2.71.
Formation & geological history
Formed when quartz replaces fibrous crocidolite (blue asbestos) through a process of pseudomorphism, where the original mineral shape is preserved but replaced by silica. The golden color comes from iron oxides. Most deposits are found in Precambrian rock formations.
Uses & applications
Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular lapidary or metaphysical collection stone.
Geological facts
Tiger's Eye exhibits a unique optical property called chatoyancy (the 'cat's-eye effect'), where bands of light shift across the surface as the stone is turned. It is considered a metamorphic rock due to the hydrothermal replacement process.
Field identification & locations
Identify in the field by its distinct parallel fibrous structure and silky golden-brown bands. It is most commonly found in South Africa, Western Australia, India, and Thailand. Collectors should look for sharp, moving light bands.
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