mineral
Chatoyant Quartz (Cat's Eye Quartz)
Silicon Dioxide (SiO2) with fibrous inclusions of Amphibole or Rutile
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Grayish-white, tan, or smoky; Luster: Vitreous to silky; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white, tan, or smoky
- Luster
- Vitreous to silky
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Physical properties
Hardness: 7 on Mohs scale; Color: Grayish-white, tan, or smoky; Luster: Vitreous to silky; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.
Formation & geological history
Formed through the hydrothermal deposition of silica within rock cavities. The chatoyant effect (cat's eye) occurs when light reflects off parallel fibrous inclusions of minerals like crocidolite or asbestiform minerals that have been replaced by quartz.
Uses & applications
Primarily used in jewelry as cabochons to highlight the optical effect, in crystal healing practices, and as a collector's specimen.
Geological facts
This optical phenomenon is called chatoyancy, derived from the French 'oeil de chat'. While chrysoberyl is the most famous cat's eye, quartz is the most common mineral to exhibit this effect naturally.
Field identification & locations
Identify in the field by rotating the stone under a single light source to see a band of light move across the surface. Frequently found in Brazil, India, Sri Lanka, and Madagascar.
