mineral

Polished jasper pebble

Microcrystalline quartz (chalcedony), usually with iron-oxide impurities

AI-generated identification · may be incorrect

Opaque brown to reddish-brown, mottled, with a glassy-to-waxy polish; Mohs hardness about 6.5–7, no visible cleavage, cryptocrystalline structure, and specific gravity around 2.5–2.7.

Identified August 21, 2026More mineral →

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Physical properties

Opaque brown to reddish-brown, mottled, with a glassy-to-waxy polish; Mohs hardness about 6.5–7, no visible cleavage, cryptocrystalline structure, and specific gravity around 2.5–2.7.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement sediments, volcanic material, or fossils, with iron oxides producing the brown-red colors. Its age varies widely, from Precambrian to recent; this specimen has been tumbled and polished.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and decorative stone; it is generally not a major construction material. Common polished pieces have modest collector value.

Geological facts

Jasper is an opaque variety of chalcedony, unlike translucent agate; color patterns reflect impurities and replacement textures. The exact variety may be called brown jasper, scenic jasper, or iron jasper.

Field identification & locations

Commonly found in silica-rich volcanic and sedimentary terrains worldwide, including the western United States, Madagascar, Brazil, India, and Australia. Identify it by its opacity, hardness, lack of cleavage, and resistance to scratching by steel; acid produces no reaction.