Rock Identifier
Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2)) — mineral
mineral

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Hardness: 6.5-7.0 (Mohs); Color: Golden to red-brown; Luster: Silky; Crystal structure: Trigonal/Hexagonal; Cleavage: None; Specific Gravity: 2.64-2.71; Chatoyant effect (cat's eye)

Hardness
6
Color
Golden to red-brown
Luster
Silky
Identified More mineral
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Physical properties

Hardness: 6.5-7.0 (Mohs); Color: Golden to red-brown; Luster: Silky; Crystal structure: Trigonal/Hexagonal; Cleavage: None; Specific Gravity: 2.64-2.71; Chatoyant effect (cat's eye)

Formation & geological history

Formed through a process called pseudomorphism where silica-rich fluids replace fibrous crocidolite (blue asbestiform mineral) while retaining the original fibrous structure. Most deposits are found in banded iron formations dating to the Proterozoic Era.

Uses & applications

Primarily used in jewelry (cabochons and beads), ornamental carvings, and as a popular lucky charm or specimen for collectors.

Geological facts

Tiger's eye demonstrates a optical phenomenon known as chatoyancy, created by light reflecting off the parallel fibers within the gem. While traditionally thought to be a replacement mineral, some research suggests it may form through a cracking and sealing vein-growth mechanism.

Field identification & locations

Identify by its distinct golden stripes and the moving band of light (chatoyancy) when tilted. Major sources include South Africa (Northern Cape Province), Australia, India, and Myanmar.