mineral
Polished brown pebble, possibly agate or jasper
Uncertain; likely microcrystalline quartz (SiO₂) if agate/jasper
AI-generated identification · may be incorrectSmall, rounded and polished, with dark brown and tan banded or mottled colors and a waxy-to-glassy luster. Likely hardness about 6.5–7 Mohs; cleavage absent, conchoidal fracture, specific gravity near 2.6. Fine surface detail is limited, so identification is provisional.
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Physical properties
Small, rounded and polished, with dark brown and tan banded or mottled colors and a waxy-to-glassy luster. Likely hardness about 6.5–7 Mohs; cleavage absent, conchoidal fracture, specific gravity near 2.6. Fine surface detail is limited, so identification is provisional.
Formation & geological history
If agate or jasper, it formed when silica-rich groundwater filled cavities in volcanic rock, probably during the Cenozoic or older; subsequent weathering rounded the fragment. The visible polish indicates human processing.
Uses & applications
Used as a tumbled collectible, lapidary material, cabochon, ornamental stone, and occasionally in jewelry; too small for construction use.
Geological facts
Agate commonly shows translucent bands, whereas jasper is generally opaque and richly colored. A strong flashlight test may reveal translucency and internal banding.
Field identification & locations
Common possibilities include Brazilian, Uruguayan, Mexican, Indian, or North American agate/jasper, but locality cannot be determined from this image. Check translucency, banding, and a white-streak test; avoid scratching unless necessary.
