metamorphic

Polished tiger’s-eye / iron-rich quartzite

Quartz (SiO₂), commonly pseudomorphic tiger’s-eye with limonite/goethite and remnants of crocidolite fibers

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; brown-gold, opaque, silky to vitreous luster, with curved banding and possible chatoyancy. Massive, fine-grained quartz with no obvious cleavage; specific gravity about 2.6–2.8.

Identified September 10, 2026More metamorphic →

Explore Polished tiger’s-eye / iron-rich quartzite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Polished tiger’s-eye / iron-rich quartzite
Scientific name: Quartz (SiO₂), commonly pseudomorphic tiger’s-eye with limonite/goethite and remnants of crocidolite fibers
Category: metamorphic
Identified: September 10, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common polished specimen; $30–$150+ for large pieces with vivid chatoyancy and attractive carving.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when quartz replaced fibrous crocidolite during low-grade metamorphism and later oxidized, producing golden-brown iron staining. Most gem-quality material formed in Precambrian rocks of the Northern Cape, South Africa.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, ornaments, and decorative objects; durable but less valuable than fine chatoyant gemstones.

Geological facts

The golden sheen results from aligned fibers reflecting light, called chatoyancy. Blue-gray unoxidized material is hawk’s-eye; red varieties are often heat-treated.

Field identification & locations

Identify it by brown-gold parallel bands, strong silky reflection when rotated, quartz-like hardness, and absence of metallic sparkle; common sources include South Africa, Western Australia, India, and Namibia.