mineral
Tiger’s-eye bracelet/bead segment
Chatoyant quartz (SiO₂), likely brown tiger’s-eye with iron-oxide alteration
AI-generated identification · may be incorrectGolden-brown to dark brown bands with silky chatoyancy, opaque to translucent, vitreous-to-waxy luster; quartz hardness is about 7 Mohs, with no obvious cleavage and density near 2.6–2.7. The piece is polished and shaped into jewelry, so natural crystal faces are absent.
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Physical properties
Golden-brown to dark brown bands with silky chatoyancy, opaque to translucent, vitreous-to-waxy luster; quartz hardness is about 7 Mohs, with no obvious cleavage and density near 2.6–2.7. The piece is polished and shaped into jewelry, so natural crystal faces are absent.
Formation & geological history
Forms when crocidolite (blue asbestos) fibers are replaced by quartz, with iron oxidation producing brown-gold color; commonly associated with Precambrian metamorphic rocks, especially in South Africa and Western Australia. Geological formation is generally Precambrian, over 500 million years old.
Uses & applications
Used for cabochons, beads, carvings, and inexpensive jewelry; also a popular lapidary and decorative stone.
Geological facts
The reflective band is caused by aligned fibrous inclusions, producing chatoyancy when cut parallel to the fibers. Blue-gray material is called hawk’s-eye, while red varieties are often called bull’s-eye.
Field identification & locations
Identify by its moving silky stripe, fibrous banding, quartz-like hardness, and lack of effervescence; glass imitations usually lack natural irregular bands. Common sources include South Africa, Australia, India, and Namibia.
