Tiger's Eye
Quartz var. Tiger's Eye (Pseudomorph of Quartz after Crocidolite) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal crystal system; microcrystalline habit (fibrous pseudomorph)
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2 (Silicon Dioxide) with inclusions of Goethite (FeO(OH))
Formation Process
Pseudomorphic formation: Quartz replaces fibrous crocidolite asbestos, retaining the fibrous structure. Iron causes the characteristic golden-brown oxided hues through hydrothermal activity.
About This Crystal
An opaque, fibrous specimen showing rhythmic golden-yellow to dark-brown bands with a silky luster on fractured surfaces. This specific rough specimen shows a distinct transition between fibrous chatoyant layers and more massive, duller matrix rock.
Physical Characteristics
Color: Golden yellow to deep brown; Streak: White; Cleavage: None; Fracture: Splintery to uneven; Specific Gravity: 2.64–2.71; Tenacity: Brittle; Fluorescence: Generally inert.
Optical Properties
Displays strong chatoyancy (cat's eye effect) due to the parallel orientation of internal fibers; Refractive Index: 1.544–1.553; Birefringence: 0.009 (often aggregates); Uniaxial positive.
Hardness & Durability
Origin Region
Griquatown West and Kuruman, South Africa; also Western Australia and India.
Hardness & Durability
Mohs Hardness: 6.5–7; Toughness: Good (due to fibrous structure); excellent stability for jewelry use.
Care & Maintenance
Safe to clean with warm soapy water; avoid ultrasonic cleaners if the specimen has numerous fractures. Store away from harder stones like Topaz or Sapphire to prevent scratching.
Rarity & Value
Common; Value is determined by the intensity of the chatoyant 'shimmer', color saturation, and lack of dull matrix. Often heat-treated to produce 'Red Tiger's Eye'.
Special Characteristics
Strong chatoyancy is the primary feature; when viewed from different angles, the golden bands appear to move or flash.
Lore & History
Historically worn by Roman soldiers for protection in battle. In traditional lore, it is considered a stone of courage, focus, and grounding, often associated with the Solar Plexus chakra.