metamorphic
Tiger's Eye (likely Hawk's Eye variant)
Pseudomorph of Quartz after Crocidolite (SiO2)
Hardness: 6.5-7 (Mohs); Color: Blue-grey to greenish-black (Hawk's eye) with golden-brown bands; Luster: Silky; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 2.64-2.71
- Hardness
- 6
- Luster
- Silky
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs); Color: Blue-grey to greenish-black (Hawk's eye) with golden-brown bands; Luster: Silky; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 2.64-2.71
Formation & geological history
Formed through a metamorphic process where quartz replaces crocidolite (asbestos) fibers while retaining the original fibrous structure (pseudomorphism). Most deposits are found in Precambrian rock formations over 2 billion years old.
Uses & applications
Primarily used as a gemstone for jewelry (cabochons, beads), decorative carvings, and as a popular specimen for rock collectors and metaphysical use.
Geological facts
It exhibits chatoyancy, an optical effect that makes it look like a cat's eye when light reflects off the fibrous inclusions. When the specimen shifts toward blue/grey, it is often called 'Hawk's Eye'.
Field identification & locations
Identify in the field by its characteristic silky luster and 'moving' light bands (chatoyancy) when rotated. It is commonly found in South Africa, Australia, and Brazil.
More like this
