mineral

Tumbled reddish-brown jasper

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

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque, reddish-brown with darker mottling, dull to mildly waxy luster, and no visible cleavage; polished/tumbled surfaces are smooth. The specimen’s rounded shape indicates human tumbling or natural abrasion.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills fractures, cavities, or sediments and becomes microcrystalline quartz, with iron oxidation producing the red-brown color. Deposits occur in many ages and settings worldwide; the exact locality cannot be determined from the image.

Uses & applications

Used for cabochons, beads, carvings, bookends, and lapidary collectibles; crushed jasper has minor decorative and aggregate uses. Common tumbled pieces have modest commercial value.

Geological facts

Jasper is a chalcedony-related rock composed mainly of quartz but is generally opaque because of abundant impurities. Color and patterns vary greatly with iron, manganese, clay, and other inclusions.

Field identification & locations

Identify it by its opacity, earthy red-brown color, very fine texture, and resistance to scratching; it should scratch glass but not be scratched by a steel knife. Common sources include India, Madagascar, Brazil, Australia, the western United States, and South Africa.