Tiger's Eye
Quartz var. Chatoyant Crocidolite · Semi-Precious Gemstone
Crystal System
Trigonal/Hexagonal system (microcrystalline); Habit is fibrous, pseudomorphous after crocidolite.
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide) with fibrous inclusions of altered Crocidolite (Na2Fe2+3Fe3+2Si8O22(OH)2)
Formation Process
Metamorphic/Hydrothermal; It forms as a pseudomorph where quartz replaces existing crocidolite (blue asbestos) fibers, retaining the fibrous structure while oxidizing the iron content.
About This Crystal
An opaque, fibrous quartz variety showcasing a characteristic silk-like luster and rich golden-brown to yellow-gold color bands. The specimen in the image appears to have a silky to sub-vitreous luster with distinct parallel banding.
Physical Characteristics
Color: Golden yellow to deep brown; Streak: White; Cleavage: None (fibrous structure); Fracture: Splintery to conchoidal; Specific Gravity: 2.64–2.71; Fluorescence: Generally inert.
Optical Properties
Refractive Index: 1.544–1.553; Birefringence: 0.009; Optical Effect: Chatoyancy (the 'cat's eye' effect caused by the reflection of light off the parallel fibrous inclusions).
Hardness & Durability
Origin Region
South Africa (Griqaland West), Western Australia, India, Burma, Namibia, and USA.
Hardness & Durability
Mohs Hardness: 6.5–7; Toughness: Good (durable for daily wear); Stability: Stable, but sensitive to strong acids.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid harsh chemicals like hydrofluoric acid; store separately to prevent scratching softer stones or being scratched by topaz/sapphire.
Rarity & Value
Common; Value is determined by the quality of chatoyancy, the richness of the gold-brown contrast, and the size of the piece. Generally inexpensive. Often heat-treated to create 'Red Tiger's Eye'.
Special Characteristics
Displays strong chatoyancy. When oriented and cut properly (especially en cabochon), a bright band of light moves across the surface as the stone is turned.
Lore & History
Historically worn by Roman soldiers for protection in battle. In folklore, it is believed to be a stone of courage, focus, and good luck, often associated with the Solar Plexus chakra in modern crystal healing.