gemstone

Blue-and-gold tiger’s-eye (likely heat-treated quartz)

Quartz, SiO₂, with crocidolite pseudomorphs; likely treated blue/gold tiger’s-eye

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; blue, gray, and golden-brown bands with silky chatoyancy; vitreous to silky luster; trigonal crystal structure and poor cleavage. The bright blue surface may reflect polishing, coating, or treatment.

Identified August 26, 2026More gemstone →

Explore Blue-and-gold tiger’s-eye (likely heat-treated quartz) in the encyclopedia →

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Physical properties

Formation & geological history

Tiger’s-eye forms when fibrous crocidolite is replaced by quartz, preserving its structure; iron oxidation creates golden-brown colors, while blue material is riebeckite-rich or less oxidized. Major deposits occur in Precambrian rocks of South Africa, western Australia, India, and Namibia.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and small collector specimens; not generally used in construction. Blue varieties are valued for contrast and chatoyancy.

Geological facts

The moving light band is caused by aligned fibrous inclusions, an optical effect called chatoyancy. Strongly vivid blue color can indicate dyed or resin-coated material rather than fully natural blue tiger’s-eye.

Field identification & locations

Identify by its silky, cat-eye-like reflective band, fibrous parallel pattern, and quartz hardness; glassy uniform color or surface peeling suggests treatment. The photo alone cannot confirm exact species or treatment.