Rock Identifier
Red jasper pebble (Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides) — sedimentary
sedimentary

Red jasper pebble

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, dense and opaque, with brick-red to reddish-brown color, dull to waxy luster, and no visible crystals or cleavage. The rounded, smooth surface indicates natural water abrasion or tumbling.

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Physical properties

Typically Mohs hardness 6.5–7, dense and opaque, with brick-red to reddish-brown color, dull to waxy luster, and no visible crystals or cleavage. The rounded, smooth surface indicates natural water abrasion or tumbling.

Formation & geological history

Usually forms when silica-rich fluids cement fine sediment or replace volcanic ash, with hematite/goethite producing the red color; deposits range from Precambrian to younger ages. Common in river gravels, deserts, and volcanic terrains.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and ornamental objects; occasionally used as a minor decorative aggregate. Common specimens have modest collector value.

Geological facts

Jasper is a cryptocrystalline form of quartz related to chert and agate, but unlike agate it is generally opaque and nonbanded. Red varieties are among the most widespread jasper types.

Field identification & locations

Identify it by its uniform red color, opacity, fine grain, high hardness, and resistance to scratching by steel; a glassy streak or conchoidal fracture supports quartz content. Found worldwide, notably in India, Madagascar, Brazil, Australia, and the western United States.