mineral

Tumbled brown jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly with chalcedony and iron oxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque brown, tan, cream, and reddish mottling; smooth tumbled surface with waxy to vitreous luster. Quartz has trigonal crystal structure, but crystals are microscopic; cleavage is absent and fracture is conchoidal.

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or replaces volcanic and sedimentary material, with iron oxides producing the brown-red colors. It may range from ancient Precambrian material to younger volcanic deposits.

Uses & applications

Used for beads, cabochons, carvings, worry stones, and decorative objects; lower-grade pieces have little industrial importance.

Geological facts

Jasper is identified by its opacity and patterns rather than visible crystals; it differs from agate, which is typically translucent and banded.

Field identification & locations

Common in volcanic and sedimentary terrains worldwide, including the western United States, Madagascar, Brazil, India, and Australia. Field tests include hardness against glass and a nonmetallic streak; avoid scratching valuable polished surfaces.