mineral
Tumbled brown chalcedony or jasper
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper
AI-generated identification · may be incorrectOpaque to slightly translucent brown-orange, with a dull to waxy luster and smooth worn surfaces; quartz hardness is about 6.5–7 Mohs, with no obvious cleavage. The visible shape appears naturally rounded or tumbled rather than crystalline.
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Physical properties
Opaque to slightly translucent brown-orange, with a dull to waxy luster and smooth worn surfaces; quartz hardness is about 6.5–7 Mohs, with no obvious cleavage. The visible shape appears naturally rounded or tumbled rather than crystalline.
Formation & geological history
Forms when silica-rich groundwater fills cavities or fractures, later colored brown-red by iron oxides; such material commonly formed in volcanic rocks during the Cenozoic or older geologic periods. Exact identification and age require testing and locality information.
Uses & applications
Used for cabochons, beads, carvings, and decorative stone; ordinary pieces have modest lapidary value.
Geological facts
Jasper is opaque and silica-rich, whereas chalcedony is typically translucent; the specimen’s lighting and small size make the distinction uncertain.
Field identification & locations
Look for quartz-like hardness, absence of cleavage, conchoidal fracture, and resistance to scratching by steel; a streak test, translucency check, and microscope examination can distinguish it from dyed glass or brick. Common worldwide, especially in volcanic regions.
