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

Tiger's Eye

Silicon Dioxide (SiO2) - Pseudomorph of Quartz after Crocidolite

Hardness: 7 (Mohs scale), Color: Golden to reddish-brown with silky luster, Structure: Trigonal/Fibrous, Cleavage: None, Specific Gravity: 2.64-2.71, Feature: Chatoyancy (cat's-eye effect).

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Physical properties

Hardness: 7 (Mohs scale), Color: Golden to reddish-brown with silky luster, Structure: Trigonal/Fibrous, Cleavage: None, Specific Gravity: 2.64-2.71, Feature: Chatoyancy (cat's-eye effect).

Formation & geological history

Formed through a transformative process where quartz replaces original crocidolite (blue asbestos) fibers, retaining the fibrous structure. Most deposits are approximately 2 billion years old.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and as a popular gemstone for lapidary collectors and metaphysical use.

Geological facts

Ancient Romans wore it for protection in battle. It is a 'pseudomorph,' meaning one mineral took the form of another. If the iron is oxidized differently, it can turn red (Bull's Eye) or remain blue (Hawk's Eye).

Field identification & locations

Identify by its distinct golden-brown bands and moving 'chatoyant' light reflection when rotated. Major sources include South Africa, Western Australia, and India. Collectors look for high luster and sharp fiber lines.