Tiger's Eye (specifically Blue Tiger's Eye or Hawk's Eye transitioning into Red/Brown Tiger's Eye)
Quartz var. Tiger's Eye (IMA-approved mineral name: Quartz) · Semi-Precious Gemstone and Decorative Stone
Crystal System
Trigonal system, commonly occurring in massive or fibrous aggregates (pseudomorphous after crocidolite)
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2 (Silicon Dioxide with fibrous amphibole/crocidolite inclusions altered to iron oxides)
Formation Process
Pseudomorphic replacement process. It begins as the blue asbestos mineral crocidolite (riebeckite), which is subsequently permeated and replaced by silica-rich solutions (quartz). Iron is oxidized or leached, resulting in the golden-brown, blue, or reddish banded colors.
About This Crystal
Tumbled, polished smooth specimen displaying a distinct chatoyant sheen (cat's eye effect). The coloration features dark navy blue to black contrasting with warm golden-brown and vivid reddish-orange bands. The luster is vitreous to silky when polished, highlighting the parallel fibrous inclusions.
Physical Characteristics
Colors include blue, golden-brown, red, and yellow with a white streak. Cleavage is absent due to microcrystalline/fibrous quartz structure. Fracture is conchoidal to uneven. Specific gravity ranges from 2.64 to 2.71. Tenacity is brittle.
Optical Properties
Singly refractive (though aggregate polarization can occur), uniaxial positive with a refractive index of approximately 1.544 to 1.553. Exhibits strong chatoyancy due to the parallel alignment of fibrous inclusions reflecting light as a moving band.
Hardness & Durability
Origin Region
Primary deposits are found in South Africa (Northern Cape Province) and Western Australia. Other notable sources include the USA, Canada, India, Brazil, and China. Forms in metamorphic environments where quartz replaces fibrous riebeckite/crocidolite.
Hardness & Durability
Mohs hardness of 7, making it durable and suitable for various types of jewelry. Good toughness because of the dense, interlocking fibrous quartz structure, though it can be sensitive to hydrofluoric acid.
Care & Maintenance
Easy to care for. Clean with warm soapy water and a soft cloth; avoid harsh chemicals and prolonged exposure to high heat or direct sunlight to prevent color alteration.
Rarity & Value
Common and widely available. Value is determined by chatoyancy intensity, symmetry of color bands, and lack of surface fractures. Typically affordable, ranging from a few dollars for tumbled stones to moderate prices for carved or high-grade cabochons. Treatments are rare, though sometimes heat is used to redden the brown stones.
Special Characteristics
Distinct chatoyancy (cat's eye effect) caused by the reflection of light off parallel fibrous channels within the stone. Blue varieties are often called Hawk's Eye, and red varieties are sometimes called Dragon's Eye.
Lore & History
Historically used as an amulet against curses and ill-wishing by ancient civilizations, including Roman soldiers who wore it for protection in battle. In modern crystal healing, it is traditionally associated with the Solar Plexus and Third Eye chakras, symbolizing courage, focus, clarity, and grounding energy (note: these are traditional beliefs, not scientific claims).