sedimentary

Red jasper (likely iron-rich chert)

Microcrystalline quartz (SiO₂) colored by hematite/goethite; possibly ferruginous chert

AI-generated identification · may be incorrect

Opaque rusty-red to brown, earthy-to-waxy luster, very fine-grained and massive with conchoidal-to-irregular fracture; Mohs hardness about 6.5–7, no visible cleavage, specific gravity roughly 2.6. The pitted surface may reflect weathering or natural vesicles, so identification from the photograph is provisional.

Identified August 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica-rich sediment or chemical precipitates become silicified and acquire iron-oxide coloration, commonly during Precambrian to younger sedimentary processes. It occurs as nodules, beds, or weathered fragments in iron-rich sedimentary terrains.

Uses & applications

Used as an ornamental and lapidary stone for cabochons, carvings, beads, and tumbled pieces; historically used for tools and occasionally as a minor aggregate. Common-quality fragments have modest commercial value.

Geological facts

Red color is mainly caused by finely dispersed hematite, while yellow-brown tones may indicate goethite or limonite. It may resemble red volcanic scoria, but jasper is typically much harder and denser.

Field identification & locations

Test an inconspicuous area: it should scratch glass and leave no streak on unglazed porcelain or only a weak reddish mark; a steel knife generally will not scratch it. Common in India, Australia, Brazil, South Africa, the United States, and Mexico.