mineral
Polished brown jasper (likely ocean or brecciated jasper)
Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides
AI-generated identification · may be incorrectOpaque brown, golden, and reddish surface with darker veining and irregular cavities; typically waxy to glossy luster and no visible cleavage. Hardness is about 6.5–7 Mohs; specific gravity approximately 2.55–2.70; composition is cryptocrystalline quartz.
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Physical properties
Opaque brown, golden, and reddish surface with darker veining and irregular cavities; typically waxy to glossy luster and no visible cleavage. Hardness is about 6.5–7 Mohs; specific gravity approximately 2.55–2.70; composition is cryptocrystalline quartz.
Formation & geological history
Forms when silica-rich fluids fill cavities or replace volcanic and sedimentary material, with iron staining producing the brown coloration; commonly Cenozoic to older, depending on locality. The specimen appears shaped and highly polished, so its natural texture is partly obscured.
Uses & applications
Used for cabochons, beads, carvings, ornamental objects, and lapidary display; occasionally used as decorative stone. Common polished pieces generally have modest commercial value.
Geological facts
Jasper is a variety of opaque chalcedony rather than a single mineral species. Color patterns may resemble breccia, landscape, or ocean jasper depending on the exact locality.
Field identification & locations
Identify by its opaque silica-rich body, glassy/waxy polish, lack of cleavage, and ability to resist scratching by steel; a streak test and hardness test can help distinguish it from resin or glass. Common sources include Madagascar, Indonesia, Brazil, Australia, Mexico, and the western United States.
