Rock Identifier
Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)) — mineral
mineral

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Hardness: 6.5–7 on Mohs scale; Color: Golden yellow to deep brown; Luster: Silky to vitreous; Crystal structure: Trigonal/Fibrous; Cleavage: None; Chatoyancy: High (cat's eye effect).

Hardness
6
Color
Golden yellow to deep brown
Luster
Silky to vitreous
Identified More mineral

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Physical properties

Hardness: 6.5–7 on Mohs scale; Color: Golden yellow to deep brown; Luster: Silky to vitreous; Crystal structure: Trigonal/Fibrous; Cleavage: None; Chatoyancy: High (cat's eye effect).

Formation & geological history

Formed through the hydrothermal replacement of crocidolite (blue asbestos) fibers by silica (quartz). This process creates a pseudomorph where the fibrous structure is preserved while the chemistry changes. Found primarily in metamorphic iron formations.

Uses & applications

Predominantly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for metaphysical or gemstone collectors.

Geological facts

The name comes from its resemblance to the eye of a tiger or cat. When the iron inclusions are less oxidized, the stone remains blue and is known as Hawk's Eye. It is the designated gemstone for the 9th wedding anniversary.

Field identification & locations

Identify by its characteristic 'chatoyancy'—the way the light band moves across the stone when it is rotated. Most commonly found in South Africa (Griqualand West), but also found in Australia, India, and the USA.