mineral

Polished brecciated jasper

Jasper, microcrystalline quartz (SiO₂), with iron-oxide and silica vein infill

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque reddish-brown with cream-white angular vein patterns, waxy to dull luster, and no visible cleavage. Its compact cryptocrystalline quartz structure gives it strong fracture resistance and typical specific gravity near 2.6.

Identified September 5, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids cement and replace volcanic or sedimentary material, with iron producing the red-brown color and later fractures filled by pale quartz or chalcedony. Deposits are generally Precambrian to younger, depending on locality.

Uses & applications

Commonly cut and polished as cabochons, palm stones, beads, carvings, and ornamental slabs; occasionally used for decorative stone. It has modest jewelry and collector value.

Geological facts

The contrasting pattern is brecciation: broken fragments were naturally recemented by mineral-rich fluids. Jasper is a variety of opaque chalcedony/microcrystalline quartz rather than a single strictly defined mineral species.

Field identification & locations

Identify it by its opaque reddish groundmass, creamy irregular veins, glassy-to-waxy polish, and inability to scratch with a steel knife if quartz-rich. Similar material occurs worldwide, notably India, Madagascar, Brazil, South Africa, and the western United States.