mineral

Tumbled brown stone, possibly tiger’s-eye

Quartz (SiO₂), likely chatoyant quartz with iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness about 7 Mohs; brown to golden-brown color, vitreous to silky luster, opaque to translucent, and no obvious cleavage. The rounded, polished shape indicates tumbling or cutting; the visible sheen may be chatoyancy, though the image is insufficient for certainty.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Tiger’s-eye forms when crocidolite fibers are pseudomorphed by quartz and later colored by iron oxides, typically in hydrothermal veins and altered rocks. It is mainly associated with Precambrian terrains, especially southern Africa.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and inexpensive collectible specimens; quartz also has major industrial uses in glass and electronics.

Geological facts

A bright moving band of reflected light is characteristic of chatoyancy (“cat’s-eye” effect). The specimen could alternatively be brown jasper or iron-stained quartz if no chatoyant band appears under directional light.

Field identification & locations

Check for a sharp, mobile silky band when rotated, glassy fracture, and lack of cleavage; it should resist scratching by steel. Common sources include South Africa, Western Australia, India, and Brazil.