mineral
Polished brecciated jasper
Jasper, microcrystalline quartz (SiO₂), with iron-oxide-rich inclusions
AI-generated identification · may be incorrectOpaque, polished stone with dark brown to black groundmass and flowing golden-orange bands; typically Mohs 6.5–7, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The banding and color likely reflect iron oxides and silica-rich veins.
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Physical properties
Opaque, polished stone with dark brown to black groundmass and flowing golden-orange bands; typically Mohs 6.5–7, vitreous to waxy luster, cryptocrystalline structure, and no visible cleavage. The banding and color likely reflect iron oxides and silica-rich veins.
Formation & geological history
Forms when silica-rich groundwater replaces or cements volcanic ash, breccia, or other sediments, with iron oxidation producing the warm bands. Jasper deposits are geologically diverse and may range from Paleozoic to Cenozoic in age.
Uses & applications
Used for cabochons, beads, carvings, bookends, and decorative polished stones; generally ornamental rather than industrial.
Geological facts
Its appearance may resemble picture jasper, brecciated jasper, or iron-rich petrified material; exact identification requires examining texture and testing hardness.
Field identification & locations
Common in volcanic and hydrothermal regions worldwide, including Oregon, Idaho, Utah, Arizona, Madagascar, and Australia. A glassy streak-free surface, opacity, and ability to scratch ordinary glass support jasper identification.
