metamorphic

Tiger's Eye (Tiger Iron / Banded Tiger's Eye)

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxides/hematite/goethite)

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on the Mohs scale; Color: golden-yellow to rich brown, with dark iron-rich bands; Luster: silky to vitreous when polished; Crystal structure: Trigonal (microcrystalline aggregate); Cleavage: none (conchoidal fracture); Specific gravity: 2.64 - 2.71.

Hardness: 6
Color: golden-yellow to rich brown, with dark iron-rich bands
Luster: silky to vitreous when polished

Identified October 25, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed via epithermal alteration and pseudomorphism where fibrous blue asbestos (crocidolite) is progressively replaced by silica (chalcedony/quartz) while preserving the parallel fibrous structure, alongside iron oxidation that produces the characteristic golden-brown hues and chatoyant effect.

Uses & applications

Extensively used in lapidary arts, jewelry (cabochons, beads, pendants), ornamental carvings, decorative spheres, and as a popular collectible polished specimen.

Geological facts

The optical illusion of moving light across the surface is known as chatoyancy, or the 'cat's-eye' effect. When layered naturally with red jasper and black hematite, it is specifically called 'Tiger Iron'.

Field identification & locations

Identifiable by its distinct silky chatoyancy (shimmering bands of light shifting upon rotation) and alternating golden-brown and dark metallic/iron layers. Major world sources include the Northern Cape Province of South Africa and Western Australia.