Tiger's Eye (Blue/Black variety, also known as Hawk's Eye)

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Dark blue-grey to black with silky bands; Luster: Silky; Crystal structure: Trigonal/Fibrous; Cleavage: None/Indistinct; Specific Gravity: 2.64-2.71

Formation & Geological History

Formed through the pseudomorphism of crocidolite (blue asbestos) by quartz. As quartz replaces the fibers, it retains the parallel fibrous structure, creating chatoyancy. It occurs in regional metamorphic environments.

Uses & Applications

Used primarily for jewelry (cabochons, beads), decorative carvings, tumbling for collectors, and in metaphysical practices.

Geological Facts

Also known as Hawk's Eye, it is essentially unfinished Tiger's Eye; if the iron levels were higher and oxidized, it would turn the familiar golden-brown color. The 'eye' effect is called chatoyancy.

Field Identification & Locations

Identify by its characteristic 'chatoyancy' (moving light bands) when rotated. Found commonly in South Africa, Australia, and parts of the USA. Look for silky luster and fibrous appearance even after polishing.

Identified on: 4/17/2026

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