mineral

Eagle Eye / Grey Tiger Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Grey, black, and silver with chatoyant bands; Luster: Silky to vitreous; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 2.64-2.71

Hardness: 6
Color: Grey, black, and silver with chatoyant bands
Luster: Silky to vitreous

Identified June 2, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: Grey, black, and silver with chatoyant bands; Luster: Silky to vitreous; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 2.64-2.71

Formation & geological history

Formed through a pseudomorphic process where silica (Quartz) replaces the fibrous mineral crocidolite, often found in metamorphic iron formations.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and as a collector's gemstone for its chatoyant effect.

Geological facts

Eagle Eye is the grey-to-black variety of Tiger's Eye. It exhibits chatoyancy (the cat-eye effect) due to the preserved fibrous structure of the original asbestos-related minerals, now fully replaced by safe quartz.

Field identification & locations

Identify by its characteristic silky chatoyance that moves when the stone is rotated under light. Found extensively in South Africa and Western Australia.

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