mineral
Tumbled red jasper
Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides
AI-generated identification · may be incorrectOpaque reddish-brown, waxy to glassy luster, very fine-grained cryptocrystalline structure, no visible cleavage; Mohs hardness about 6.5–7 and specific gravity approximately 2.5–2.9. The smoothly polished shape indicates a tumbled specimen.
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Physical properties
Opaque reddish-brown, waxy to glassy luster, very fine-grained cryptocrystalline structure, no visible cleavage; Mohs hardness about 6.5–7 and specific gravity approximately 2.5–2.9. The smoothly polished shape indicates a tumbled specimen.
Formation & geological history
Forms when silica-rich groundwater fills cavities or replaces sediments and volcanic material, with iron oxides producing the red color; individual deposits range from Precambrian to much younger. Common sources include India, Madagascar, Brazil, Uruguay, South Africa, and the United States.
Uses & applications
Used for cabochons, beads, carvings, tumbled stones, ornamental objects, and lapidary practice; it has little industrial value compared with quartz aggregate.
Geological facts
Jasper is a variety of chalcedony or microcrystalline quartz, though the term also broadly covers opaque, silica-rich rocks. Color and patterns vary with hematite, goethite, clay, and other inclusions.
Field identification & locations
Identify it by its opaque red-brown body, fine texture, lack of cleavage, and inability to scratch glass only weakly or not at all; a steel file generally does not scratch fresh jasper easily. Natural jasper commonly occurs as nodules, veins, or silicified volcanic and sedimentary layers.
