mineral
Tumbled brown stone, possibly tiger’s-eye
Quartz (SiO₂), likely chatoyant quartz with iron-oxide inclusions
AI-generated identification · may be incorrectHardness 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.
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Physical properties
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.
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.
