mineral
Tumbled dark reddish-brown stone, possibly red jasper
Jasper, microcrystalline quartz (SiO₂), likely iron-oxide colored
AI-generated identification · may be incorrectOpaque, reddish-brown, smooth and rounded from tumbling, with a dull to mildly waxy luster. Hardness about 6.5–7 Mohs; no visible cleavage; typically cryptocrystalline quartz with specific gravity near 2.6.
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Physical properties
Opaque, reddish-brown, smooth and rounded from tumbling, with a dull to mildly waxy luster. Hardness about 6.5–7 Mohs; no visible cleavage; typically cryptocrystalline quartz with specific gravity near 2.6.
Formation & geological history
Jasper forms when silica-rich fluids replace or cement volcanic or sedimentary material, with iron oxides producing the red-brown color. Formation ages vary widely, commonly Precambrian to younger; the specimen has been human-polished.
Uses & applications
Used for cabochons, beads, carvings, polished stones, and decorative objects; common pieces have modest collector value.
Geological facts
Jasper is a variety of opaque chalcedony or microcrystalline quartz. Its patterns and colors reflect impurities such as hematite, goethite, clay, or manganese minerals.
Field identification & locations
Identify it by its opaque body, earthy red-brown color, smooth polish, and inability to scratch with a copper coin; it should scratch ordinary glass. Common sources include India, Madagascar, Brazil, Australia, and the western United States.
