mineral

Polished red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides.

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, opaque, reddish-brown with black or gray mottling, and a glassy to waxy luster when polished; quartz crystals are too fine-grained to see.

Identified August 10, 2026More mineral →

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Physical properties

Typically Mohs hardness 6.5–7, opaque, reddish-brown with black or gray mottling, and a glassy to waxy luster when polished; quartz crystals are too fine-grained to see.

Formation & geological history

Forms when silica-rich groundwater cements volcanic ash, sediments, or fractured rock, with iron producing the red coloration. Deposits occur in many ages, commonly in volcanic and hydrothermal environments.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and ornamental objects; it has little industrial value compared with ordinary quartz.

Geological facts

Jasper is a variety of chalcedony or microcrystalline quartz, though the term is often used broadly for opaque silica-rich rocks. Color patterns vary greatly by locality.

Field identification & locations

Identify it by its opaque red body, fine texture, lack of visible cleavage, and ability to scratch glass; a steel blade usually does not scratch it. Common sources include India, Madagascar, Brazil, Australia, and the western United States.