Tiger's Eye
Quartz var. Tiger's Eye · Semi-Precious Gemstone / Ornamental Stone
Crystal System
Trigonal system; typically forms as a pseudomorph after fibrous crocidolite (riebeckite), massive or compact habit.
Mineral Group
Silicates (Subgroup: Tectosilicates)
Chemical Formula
SiO2 (Silicon Dioxide with inclusions of crocidolite fibers)
Formation Process
Pseudomorphous replacement process where silica (quartz) slowly replaces fibrous blue asbestos (crocidolite) while maintaining the original fibrous structure, often accompanied by iron oxide staining.
About This Crystal
A polished, tumbled gemstone displaying rich golden-brown to yellow-brown body colors interspersed with dark brown and black bands. It has a silky luster and exhibits a distinct moving line of light known as chatoyancy, giving it a cat's-eye appearance due to its parallel fibrous structure.
Physical Characteristics
Colors range from golden yellow, golden brown, to deep brownish-red (ox-eye). Streak is white. Cleavage is none, fracture is conchoidal to uneven. Specific gravity is approximately 2.64 to 2.71. Tenacity is brittle. Displays silky luster and typically opaque to translucent.
Optical Properties
Uniaxial positive with refractive index ranging from 1.544 to 1.553. Birefringence is 0.009. The defining optical property is chatoyancy (cat's-eye effect), caused by the reflection of light from the parallel fibrous inclusions within the quartz matrix.
Hardness & Durability
Origin Region
Primary sources include South Africa, Western Australia, Western USA, India, and Brazil. Forms in sedimentary formations altered by metasomatism.
Hardness & Durability
Mohs hardness of 7 (similar to quartz), making it durable enough for most jewelry uses. Toughness is good due to the interlocking fibrous microcrystalline structure.
Care & Maintenance
Easy to care for; can be cleaned safely with warm soapy water and a soft brush. Avoid harsh chemical cleaners and prolonged exposure to high heat, which can alter the iron oxide colors. Store separately from softer stones to prevent scratching.
Rarity & Value
Common and widely available. Value depends on the intensity and symmetry of the chatoyant band, color saturation, and absence of flaws. Generally inexpensive, making it a popular choice for carvings, beads, and cabochons.
Special Characteristics
Famous for its strong chatoyancy (cat's-eye effect). Heat treatment can turn the golden-brown variant into a reddish-brown variant known as ox-eye or bull's-eye, and acid treatment can yield blue tiger's eye, also known as hawk's eye.
Lore & History
Historically used as an amulet and talisman in ancient Egypt and Rome to protect against curses and grant courage to soldiers in battle. In modern crystal healing, it is traditionally associated with the Solar Plexus chakra, representing willpower, confidence, and grounding energy (note: these are traditional beliefs, not scientific claims).