mineral

Tumbled jasper, likely red jasper

Microcrystalline quartz (SiO₂), chalcedony variety with iron-oxide impurities

AI-generated identification · may be incorrect

Opaque dark reddish-brown, smooth tumbled surface, dull to weakly waxy luster, no visible cleavage; Mohs hardness about 6.5–7 and specific gravity roughly 2.6. The pale patches may be quartz, weathering, or surface abrasion.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater replaces or fills cavities in volcanic rocks, with iron oxides producing the red-brown color; deposits range from Precambrian to younger volcanic settings. Its rounded shape indicates human tumbling or natural abrasion.

Uses & applications

Used for cabochons, beads, carvings, lapidary items, and inexpensive decorative specimens; too opaque and irregular for high-value faceting.

Geological facts

Jasper is an opaque variety of chalcedony, unlike translucent agate. Red coloration commonly comes from hematite or other iron oxides.

Field identification & locations

Identify by its opaque red-brown color, very fine grain, glass-scratching hardness, and lack of visible crystals; common sources include India, Madagascar, Brazil, Australia, and the western United States. Acid does not normally react, and a steel knife should not scratch it easily.