mineral

Polished brown jasper pebble

Jasper, microcrystalline quartz (SiO₂) with iron-oxide impurities

AI-generated identification · may be incorrect

Typically Mohs 6.5–7; opaque brown to reddish-brown with black veining, vitreous-to-waxy luster, cryptocrystalline quartz structure, and no visible cleavage. The smooth surface indicates tumbling or polishing.

Identified September 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or cement volcanic or sedimentary material, with iron oxides producing the brown-red coloration; individual pieces may range from Paleozoic to recent gravel deposits.

Uses & applications

Used for cabochons, beads, carvings, decorative objects, and inexpensive collectible polished stones; rarely used as a minor ornamental stone in construction.

Geological facts

Jasper is technically an impure, opaque variety of chalcedony or microcrystalline quartz. Dark lines may represent iron/manganese-rich fractures or breccia boundaries rather than fossils.

Field identification & locations

Identify by its opacity, earthy red-brown color, glassy polish, and high hardness—it should resist scratching by a steel knife but not quartz. Commonly collected from volcanic terrains and alluvial gravels worldwide, including India, Madagascar, Brazil, and the western United States.