mineral
Tumbled jasper (likely brown/yellow jasper)
Microcrystalline quartz, SiO₂, typically with iron-oxide and clay impurities
AI-generated identification · may be incorrectOpaque mustard-brown, reddish-brown stone with a matte-to-waxy luster and rounded, polished surfaces. Quartz hardness is about Mohs 6.5–7; no visible cleavage, cryptocrystalline structure, and typical specific gravity near 2.6.
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Physical properties
Opaque mustard-brown, reddish-brown stone with a matte-to-waxy luster and rounded, polished surfaces. Quartz hardness is about Mohs 6.5–7; no visible cleavage, cryptocrystalline structure, and typical specific gravity near 2.6.
Formation & geological history
Jasper forms when silica-rich fluids replace or cement volcanic or sedimentary material, with iron oxides producing the warm colors; ages vary widely, commonly Paleozoic to younger. This specimen has been mechanically tumbled and polished.
Uses & applications
Used as an inexpensive lapidary stone for cabochons, beads, carvings, and decorative objects; it has limited industrial value.
Geological facts
Jasper is an opaque variety of chalcedony or microcrystalline quartz, unlike translucent agate. Color patterns may reflect iron staining, volcanic ash, or sedimentary layering.
Field identification & locations
Identify it by its opacity, earthy coloration, waxy surface, and resistance to scratching; quartz should scratch glass, though coatings or alteration can affect testing. Common sources include India, Madagascar, Brazil, the United States, and Australia.
