Rock Identifier
Tiger's Eye (Tiger's Eye (a variety of Chalcedony, which is a microcrystalline quartz with fibrous inclusions of oxidized crocidolite)) — Mineral
Mineral

Tiger's Eye

Tiger's Eye (a variety of Chalcedony, which is a microcrystalline quartz with fibrous inclusions of oxidized crocidolite)

Hardness: 6.5-7 on the Mohs scale. Color: Golden to reddish-brown with a silky to vitreous luster. Features characteristic banding and chatoyancy (cat's eye effect) due to fibrous inclusions. Crystal Structure: Trigonal, though typically found in massive fibrous aggregates. Cleavage: None. Specific Gravity: 2.64-2.71.

Hardness
6
Color
Golden to reddish-brown with a silky to vitreous luster
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Physical properties

Hardness: 6.5-7 on the Mohs scale. Color: Golden to reddish-brown with a silky to vitreous luster. Features characteristic banding and chatoyancy (cat's eye effect) due to fibrous inclusions. Crystal Structure: Trigonal, though typically found in massive fibrous aggregates. Cleavage: None. Specific Gravity: 2.64-2.71.

Formation & geological history

Tiger's Eye is formed when quartz replaces bundles of crocidolite (blue asbestos) fibers. The iron within the crocidolite oxidizes during this process, giving the quartz its golden-brown color. The fibrous structure of the original crocidolite is preserved by the quartz and creates the chatoyant effect. This replacement typically occurs in metamorphic rocks as a result of hydrothermal alteration. Geological Age: Varies depending on location, but generally associated with ancient metamorphic rock formations.

Uses & applications

Predominantly used as a gemstone in jewelry (cabochons, beads, carvings) due to its unique optical properties. Also popular in ornamental objects and as a decorative stone. In metaphysical beliefs, it is often used for protection, grounding, and promoting courage and willpower.

Geological facts

Tiger's Eye is a pseudomorph of quartz, meaning it formed as one mineral (crocidolite, a type of asbestos) and was later replaced by another (quartz) while retaining the original fibrous structure. This replacement process, combined with oxidation of iron, gives it its distinctive golden-brown color and chatoyancy. It has been used as a protective stone throughout history and is often associated with courage and confidence.

Field identification & locations

To identify in the field: Look for its distinctive golden to reddish-brown color with a characteristic wavy, iridescent sheen (chatoyancy) that moves across the surface as the stone is rotated, resembling a cat's eye. It often appears in masses or veins. Common locations: Major deposits are found in South Africa (especially the Northern Cape Province), Australia, India, Thailand, and the USA (Arizona). Tips for collectors: Polished specimens best showcase the chatoyancy. Beware of imitations; genuine Tiger's Eye will have natural variations in the banding and a clear cat's eye effect.