mineral
Tumbled red jasper
Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides
AI-generated identification · may be incorrectTypically Mohs hardness 6.5–7, opaque brick-red to reddish-brown, with a waxy to glassy luster; cryptocrystalline quartz has no visible cleavage and conchoidal fracture. The rounded, glossy form indicates tumbling and polishing.
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Physical properties
Typically Mohs hardness 6.5–7, opaque brick-red to reddish-brown, with a waxy to glassy luster; cryptocrystalline quartz has no visible cleavage and conchoidal fracture. The rounded, glossy form indicates tumbling and polishing.
Formation & geological history
Forms when silica-rich groundwater replaces or fills cavities and fractures in volcanic or sedimentary rocks, with iron producing the red color; deposits range from Precambrian to younger ages. Common sources include India, Madagascar, Brazil, Australia, and the western United States.
Uses & applications
Used for beads, cabochons, carvings, polished stones, and lapidary décor; historically used for tools and ornamental objects. Common tumbled pieces generally have modest collector value.
Geological facts
Jasper is a variety of chalcedony or microcrystalline quartz, though the term is often used broadly for opaque silica-rich rocks. Color intensity and patterns depend on hematite, goethite, and other iron minerals.
Field identification & locations
Identify by its opaque red-brown color, very fine texture, hardness, and lack of cleavage; it should scratch glass but not be scratched by a steel blade. The specimen appears commercially tumbled rather than naturally rounded.
