Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with Iron Oxide)
Rock Type: metamorphic

Physical Properties
Hardness: 6.5-7 (Mohs scale); Color: Golden yellow to brown; Luster: Silky; Crystal structure: Trigonal/Fibrous; Cleavage: None; Specific gravity: 2.64-2.71
Formation & Geological History
Formed when quartz replaces the fibrous mineral crocidolite through pseudomorphism, often occurring in folded iron-rich metamorphic rocks. Most deposits are Proterozoic in age (approx. 2 billion years old).
Uses & Applications
Primarily used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for metaphysical and mineral collectors.
Geological Facts
The characteristic 'cat's eye' effect is called chatoyancy, caused by parallel fibers of quartz reflecting light. It was once considered quite rare and valuable until large deposits were found.
Field Identification & Locations
Identify by its distinct golden-brown banding and chatoyant shimmer when rotated in the light. Commonly found in South Africa, Western Australia, and parts of India and Brazil.
Identified on: 4/19/2026
Mode: Standard