mineral
Polished brown-green jasper
Jasper, microcrystalline quartz (SiO₂), commonly with iron-oxide and chlorite inclusions
AI-generated identification · may be incorrectOpaque, waxy to glassy luster; brown, reddish-brown, and olive-green coloration with irregular internal patches. Mohs hardness 6.5–7, no cleavage, microcrystalline/trigonal quartz structure, specific gravity about 2.5–2.7.
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Physical properties
Opaque, waxy to glassy luster; brown, reddish-brown, and olive-green coloration with irregular internal patches. Mohs hardness 6.5–7, no cleavage, microcrystalline/trigonal quartz structure, specific gravity about 2.5–2.7.
Formation & geological history
Forms when silica-rich fluids replace or fill cavities in volcanic rocks, with iron and other impurities producing the colors; ages vary widely, commonly Paleozoic to Mesozoic or younger. This specimen is tumbled and highly polished.
Uses & applications
Used for cabochons, beads, carvings, ornaments, and lapidary collections; occasionally used as decorative stone. Usually modest commercial value.
Geological facts
Jasper is a variety of chalcedony or microcrystalline quartz distinguished by its opacity and abundant impurities. Green areas may reflect chlorite, epidote, or other mineral inclusions.
Field identification & locations
Identify by its opaque appearance, hardness, conchoidal fracture, and inability to scratch with a steel knife while scratching glass. Common sources include India, Madagascar, Brazil, Australia, and the western United States.
