Tiger's Eye (Rough)
Quartz (Pseudomorph after Riebeckite var. Crocidolite) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal crystal system; displays a fibrous, chatoyant habit due to pseudomorphism.
Mineral Group
Silicates; Tectosilicate (Quartz group)
Chemical Formula
SiO2 (Silicon Dioxide) with inclusions of Goethite (FeO(OH))
Formation Process
Metamorphic/Hydrothermal: Formed as a pseudomorph when quartz replaces parallel fibers of crocidolite (blue asbestos) and is later oxidized by iron to turn gold-brown.
About This Crystal
A rough, fibrous fragment approximately 3cm in length. It displays a golden-brown to dark brown color with a distinct parallel-fibrous texture and a silky luster. The specimen is opaque and shows a characteristic chatoyant shimmer even in its unpolished state.
Physical Characteristics
Color: Gold-brown, yellow, and dark brown; Streak: Yellow-brown; Cleavage: None (Quartz has none, but it breaks along fibers); Fracture: Splintery; Specific Gravity: 2.64–2.71; Fluorescence: Typically none.
Optical Properties
Displays chatoyancy (cat's eye effect) caused by the reflection of light off the parallel fibrous inclusions. Doubly refractive (Quartz base).
Hardness & Durability
Origin Region
Primarily Griqualand West, South Africa; also found in Western Australia and Myanmar.
Hardness & Durability
Mohs Hardness: 6.5–7; Toughness: Fair to Good; Stability: Stable under normal conditions but sensitive to hydrofluoric acid.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid harsh chemicals and ultrasonic cleaners if the stone has significant surface-reaching fractures. Store separately from harder gemstones like Topaz or Sapphire to prevent scratching.
Rarity & Value
Common; Value is determined by the strength of chatoyancy, richness of color, and size. Rough specimens are inexpensive, often sold by weight.
Special Characteristics
Chatoyancy is the defining feature; when polished into a cabochon, it creates a moving band of light. Also demonstrates pseudomorphism where one mineral takes the form of another.
Lore & History
Historically worn by Roman soldiers for protection in battle. In traditional crystal lore, it is associated with the Solar Plexus chakra and is believed to promote courage, clarity, and personal power.