metamorphic
Polished brown jasper
Jasper, microcrystalline quartz (SiO₂) with iron-oxide impurities
AI-generated identification · may be incorrectOpaque reddish-brown to gray-brown, waxy to vitreous luster, typically Mohs 6.5–7, with no visible cleavage and conchoidal fracture. The pale linear markings may be quartz veins or surface fractures; density is about 2.6 g/cm³.
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Physical properties
Opaque reddish-brown to gray-brown, waxy to vitreous luster, typically Mohs 6.5–7, with no visible cleavage and conchoidal fracture. The pale linear markings may be quartz veins or surface fractures; density is about 2.6 g/cm³.
Formation & geological history
Jasper forms when silica-rich fluids cement or replace sedimentary and volcanic material, with iron oxides producing the brown-red color; many deposits are Paleozoic to younger. This specimen has been tumbled or polished.
Uses & applications
Used for cabochons, beads, carvings, decorative objects, and ornamental stone; it has little industrial use compared with ordinary quartz.
Geological facts
Jasper is a variety of opaque chalcedony or microcrystalline quartz, and its patterns vary widely by locality. Similar brown stones may include brecciated jasper, chert, or iron-rich quartzite.
Field identification & locations
Identify it by its opaque appearance, fine texture, glass-scratching hardness, and lack of visible individual crystals; a steel file should not easily scratch it. Common sources include India, Madagascar, Brazil, Australia, and the western United States.
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