mineral

Tumbled brown jasper (likely orbicular or brecciated jasper)

Jasper, microcrystalline quartz/chalcedony; SiO₂

AI-generated identification · may be incorrect

Opaque, smoothly polished, brown to mustard with dark mottling and possible subtle brecciation; typically dull to waxy luster and no visible crystal faces. Mohs hardness 6.5–7, conchoidal fracture, specific gravity about 2.55–2.70; cleavage absent.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater replaces or cements volcanic ash, sediments, or rock fragments, often incorporating iron oxides that create brown, red, and yellow colors. Deposits range from Precambrian to recent, depending on locality.

Uses & applications

Used as a lapidary stone for tumbled stones, cabochons, carvings, beads, and ornamental objects; also collected as an attractive common gemstone.

Geological facts

Jasper is a variety of opaque chalcedony or microcrystalline quartz rather than a single precisely defined mineral species. Iron staining commonly produces its warm brown coloration.

Field identification & locations

Identify it by opacity, fine-grained texture, strong polish, hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel knife. Common sources include the western United States, Madagascar, Brazil, India, and Australia.