Rock Identifier
Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2)) — gemstone
gemstone

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Hardness: 7 on Mohs scale, Color: Golden yellow to reddish-brown, Luster: Silky to vitreous, Crystal System: Trigonal (microcrystalline quartz), Cleavage: None, Specific Gravity: 2.64-2.71

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Physical properties

Hardness: 7 on Mohs scale, Color: Golden yellow to reddish-brown, Luster: Silky to vitreous, Crystal System: Trigonal (microcrystalline quartz), Cleavage: None, Specific Gravity: 2.64-2.71

Formation & geological history

Formed when fibrous blue asbestos (crocidolite) is gradually replaced by chalcedony quartz while maintaining the original fibrous structure. Iron oxides present during the process impart the characteristic golden brown color. Major deposits originate from Proterozoic iron formations.

Uses & applications

Widely used in lapidary arts, jewelry making (cabochons, beads, rings), ornamental carvings, and spiritual/healing crystal collections.

Geological facts

Displays a striking optical effect known as chatoyancy or the 'cat's-eye effect,' where light reflects off internal parallel fibers, creating a shimmering band across the polished surface.

Field identification & locations

Identified by its distinctive golden-brown silky luster and chatoyant bands that move as the specimen is tilted under light. Commonly mined in South Africa, Western Australia, India, Burma, and Brazil.