mineral

Tumbled red jasper (likely brecciated jasper)

Jasper, microcrystalline quartz (SiO₂) with iron-oxide inclusions

AI-generated identification · may be incorrect

Opaque reddish-brown to black, vitreous-to-waxy luster, polished surface, and irregular brecciation or matrix patterns. Mohs hardness 6.5–7; no visible cleavage; specific gravity about 2.5–2.7; cryptocrystalline quartz structure.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or cement fine-grained sediments or volcanic material, with iron oxides producing the red color. Deposits occur in many ages, commonly in hydrothermal and volcanic terrains.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and ornamental objects; too small a piece for construction use. Common polished specimens generally have modest collector value.

Geological facts

Jasper is an opaque variety of chalcedony or microcrystalline quartz, and its patterns are caused by impurities, brecciation, or mineral replacement. The dark areas may be manganese or iron-rich matrix rather than separate crystals.

Field identification & locations

Identify it by its opaque red-brown color, black inclusions, glassy polish, and inability to scratch with a steel knife easily; glassy red slag can look similar. Common sources include India, Madagascar, Brazil, the United States, and Australia.