mineral

Tumbled jasper (likely red/brown jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored by iron oxides

AI-generated identification · may be incorrect

Opaque dark reddish-brown, fine-grained, waxy to dull luster, with faint pale inclusions and conchoidal fracture; Mohs hardness about 6.5–7, no cleavage, specific gravity about 2.6. The rounded edges indicate tumbling or polishing.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich groundwater replaces or fills cavities in volcanic or sedimentary rocks, with iron oxides producing the red-brown color. Deposits are commonly Paleozoic to Cenozoic, though exact age depends on locality.

Uses & applications

Used for cabochons, beads, carvings, decorative objects, and inexpensive lapidary material; this small tumbled piece is primarily a collector or craft specimen.

Geological facts

Jasper is an opaque variety of chalcedony, unlike transparent quartz varieties such as amethyst. Its patterns and colors vary greatly with impurities and formation environment.

Field identification & locations

Identify it by its opaque earthy color, very fine texture, lack of visible crystals, and resistance to scratching glass; a steel nail generally will not scratch it. Common sources include Brazil, India, Madagascar, Mexico, the United States, and Australia.