mineral

Polished brown jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly containing iron-oxide impurities

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, opaque, brown to reddish-brown, with a waxy-to-glassy luster after polishing; cryptocrystalline quartz has no visible crystal faces or cleavage, and specific gravity is about 2.5–2.7.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or cement volcanic ash, sediment, or breccia, with iron oxides producing the brown coloration. Deposits occur in many ages, commonly in volcanic and hydrothermal environments.

Uses & applications

Used for cabochons, beads, carvings, worry stones, and ornamental objects; durable enough for small decorative applications but generally modest in gem value.

Geological facts

The specimen appears tumbled or polished and may show natural fractures or brecciation healed by darker material. Jasper is a variety of chalcedony/microcrystalline quartz, though its opaque, impurity-rich appearance distinguishes it from translucent agate.

Field identification & locations

Identify by its opacity, earthy iron-rich color, fine grain, and ability to take a smooth polish; it should resist scratching by a steel blade more than softer glassy stones. Common sources include India, Brazil, Madagascar, Australia, and the western United States.