Tiger's Eye
Pseudomorph of Quartz after Crocidolite · Semi-Precious Gemstone / Ornamental Stone
Crystal System
Trigonal (as quartz replacing the fibrous monoclinic habit of crocidolite)
Mineral Group
Silicates (Tectosilicate)
Chemical Formula
SiO2 (with inclusions of oxidized crocidolite [Na2(Mg,Fe)3Al2Si8O22(OH)2])
Formation Process
Pseudomorphic replacement; it begins as blue asbestos (crocidolite) which is gradually replaced by silica (quartz) while maintaining the original fibrous structure. The iron in the fibers oxidizes to goethite, creating the golden-brown color.
About This Crystal
An opaque, fibrous macrocrystalline quartz displaying a silky luster and striking golden to red-brown color bands. In the image, the specimen is a polished sphere exhibiting chatoyancy, where light reflects off the parallel internal fibers.
Physical Characteristics
Color: Golden yellow to deep brown; Streak: Yellow-brown; Cleavage: None; Fracture: Conchoidal to splintery (following fiber lines); Specific Gravity: 2.64–2.71; Non-fluorescent.
Optical Properties
Displays strong chatoyancy (cat's eye effect); Refractive Index: 1.544–1.553; Uniaxial positive; Opaque to translucent in thin sections.
Hardness & Durability
Origin Region
South Africa (Northern Cape), Australia, Myanmar, India, and Namibia; typically found in iron-rich sedimentary formations.
Hardness & Durability
Mohs hardness: 6.5–7.0; Toughness: Good (due to fibrous structure); Highly durable and suitable for all jewelry types.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid harsh chemicals and ultrasonic cleaners if the stone has surface-reaching fractures. Store separately to prevent scratching softer stones.
Rarity & Value
Common; Value is driven by the intensity of the chatoyant 'shimmer', color saturation, and quality of the polish. Blue varieties (Hawk's Eye) and red varieties (partially heat-treated) are also common.
Special Characteristics
Strong chatoyancy caused by the reflection of light off the parallel mineral fibers within the quartz matrix.
Lore & History
Historically worn by Roman soldiers for protection in battle and used in ancient Egypt for the eyes of deity statues. Traditionally associated with the Solar Plexus chakra, courage, and grounding energy.