mineral

Tumbled brown jasper (likely common jasper or chert)

Microcrystalline quartz, SiO₂, chiefly chalcedony/quartz with iron-oxide impurities

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque brown to reddish-brown, with a resinous to waxy polished luster and no visible cleavage. Its rounded shape and glossy surface indicate mechanical tumbling; specific gravity is typically about 2.6.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or cement volcanic, sedimentary, or organic material, with iron oxides producing the brown color. Jasper deposits range from Precambrian to recent; the specimen’s exact age and locality cannot be determined visually.

Uses & applications

Used for tumbled stones, cabochons, carvings, beads, and ornamental objects; occasionally used as aggregate or decorative stone. Common pieces have modest collecting value.

Geological facts

Jasper is an opaque variety of chalcedony, unlike transparent gemstone-grade quartz. Brown coloration commonly reflects hematite or goethite inclusions.

Field identification & locations

Identify it by its opaque earthy color, very fine texture, glassy-to-waxy polish, lack of cleavage, and inability to scratch it with a steel knife easily; it should scratch ordinary glass. Common sources include India, Brazil, Madagascar, Australia, and the western United States.