mineral
Tumbled brown jasper
Microcrystalline quartz (SiO₂), commonly with iron-oxide inclusions
AI-generated identification · may be incorrectOpaque, polished stone with cream, ochre, and dark brown-black patches; vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, Mohs hardness about 6.5–7, specific gravity approximately 2.6.
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Physical properties
Opaque, polished stone with cream, ochre, and dark brown-black patches; vitreous to waxy luster, cryptocrystalline structure, no visible cleavage, Mohs hardness about 6.5–7, specific gravity approximately 2.6.
Formation & geological history
Jasper forms when silica-rich fluids replace or cement volcanic and sedimentary material, with iron oxides producing the warm colors. The specimen is human-tumbled and polished; its precise geological age and locality cannot be determined visually.
Uses & applications
Used for cabochons, beads, carvings, polished stones, lapidary items, and inexpensive jewelry; it has little industrial use compared with quartzite or agate.
Geological facts
Jasper is an opaque variety of chalcedony or microcrystalline quartz, unlike translucent agate. Color patterns depend mainly on hematite, goethite, and other iron-bearing minerals.
Field identification & locations
Identify it by its opaque appearance, smooth waxy polish, hardness, and lack of cleavage; a steel file should barely scratch it, while glass is commonly scratched. Jasper occurs worldwide, especially in volcanic terrains and silica-rich sedimentary beds.
