mineral

Polished brown jasper

Microcrystalline quartz/chalcedony (SiO₂), iron-oxide-rich jasper

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque brown to black with rusty yellow-brown mottling, glassy to waxy luster, and no visible cleavage. It is dense and cryptocrystalline, commonly showing a smooth tumbled polish.

Identified September 3, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic ash, sediments, or other rocks, with iron oxides producing the brown coloration. Most examples are geologically ancient, commonly Paleozoic or older, though the specimen’s exact age and locality cannot be determined from the image.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, decorative objects, and ornamental stone; rarely used as a minor aggregate or building stone.

Geological facts

The specimen appears human-tumbled and polished rather than naturally weathered. Brown jasper is often marketed under locality or trade names, but appearance alone cannot establish a specific variety.

Field identification & locations

Identify it by its opaque coloration, fine texture, strong polish, and lack of distinct crystals; it should not scratch easily with a steel knife, though testing can damage it. Common sources include India, Brazil, Madagascar, Mexico, and the western United States.