metamorphic
Tiger's Eye (Blue/Golden mix)
Pseudomorph of Quartz after Crocidolite (SiO2)
Hardness: 6.5–7.0 (Mohs scale); Color: Golden brown, blue-grey, or black; Luster: Silky to vitreous; Crystal structure: Trigonal/Fibrous; Chatoyancy: Strong optic effect; Specific gravity: 2.64–2.71
- Hardness
- 6
- Color
- Golden brown, blue-grey, or black
- Luster
- Silky to vitreous
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Physical properties
Hardness: 6.5–7.0 (Mohs scale); Color: Golden brown, blue-grey, or black; Luster: Silky to vitreous; Crystal structure: Trigonal/Fibrous; Chatoyancy: Strong optic effect; Specific gravity: 2.64–2.71
Formation & geological history
Formed through the pseudomorphism of crocidolite (asbestos) by quartz. As quartz replaces the fibrous mineral, it retains the structure, creating a chatoyant effect. Found in iron formations and Precambrian-aged deposits.
Uses & applications
Primarily used in jewelry (cabochons, beads), decorative carvings, spiritual/metaphysical collecting, and lapidary arts.
Geological facts
Commonly known as Hawk's Eye when it is blue, and Tiger's Eye when golden. This specimen shows a mix, indicating partial oxidation of the iron within the structure. It is a 'chatoyant' gemstone, meaning it reflects light like a cat's eye.
Field identification & locations
Identify in the field by moving it under a light source to see the 'shimmering' bands move (chatoyancy). It is most commonly sourced from South Africa, Western Australia, and Namibia. For collectors, look for high silky luster and no visible cracks.
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