Metamorphic
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions of Iron Oxide)
Hardness: 6.5-7.0 (Mohs scale), Color: Golden to red-brown with silky luster, Structure: Trigonal/Fibrous, Cleavage: None, Specific Gravity: 2.64-2.71. It exhibits chatoyancy (the 'cat's eye' effect).
- Hardness
- 6
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Physical properties
Hardness: 6.5-7.0 (Mohs scale), Color: Golden to red-brown with silky luster, Structure: Trigonal/Fibrous, Cleavage: None, Specific Gravity: 2.64-2.71. It exhibits chatoyancy (the 'cat's eye' effect).
Formation & geological history
Formed through a process of pseudomorphism where quartz replaces the fibrous mineral crocidolite (blue asbestos). The iron within the fibers oxidizes to a golden brown. Primary deposits are over 2 billion years old (Proterozoic era).
Uses & applications
Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular semi-precious stone for collectors and metaphysical practitioners.
Geological facts
Tiger's Eye is a classic example of a 'pseudomorph' where one mineral replaces another while retaining the original mineral's shape. It was once considered a very rare and expensive gemstone until large deposits were discovered in South Africa in the late 1800s.
Field identification & locations
Identify in the field by its distinct golden-yellow bands and the shifting light effect when rotated. Primarily found in the Northern Cape Province of South Africa, Western Australia, India, and Myanmar.
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