mineral

Weathered brown stone, likely chert or iron-stained quartzite

Microcrystalline quartz (SiO₂), probable chert; identification is limited by the image

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; orange-brown, fine-grained, dull to waxy luster, massive structure, and no visible cleavage. The rounded shape and surface coloration indicate weathering or abrasion.

Identified August 27, 2026More mineral →

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Physical properties

Hardness about 6.5–7 Mohs; orange-brown, fine-grained, dull to waxy luster, massive structure, and no visible cleavage. The rounded shape and surface coloration indicate weathering or abrasion.

Formation & geological history

Chert forms when silica-rich groundwater replaces or precipitates within sediment, commonly during the Paleozoic–Cenozoic; quartzite forms when sandstone is metamorphosed. This fragment may have been transported in pavement aggregate or natural gravel.

Uses & applications

Common chert is used historically for sharp tools and occasionally aggregate; quartzite is used as construction stone. This small fragment has negligible jewelry or commercial value.

Geological facts

Chert commonly produces a sharp conchoidal fracture and may contain fossil remnants; iron oxides create the orange coloration. The surrounding material appears to be asphalt aggregate, so the specimen may be road debris rather than a natural outcrop sample.

Field identification & locations

Test for a glass-like scratch on an ordinary steel file or glass surface, though this can damage it; inspect for conchoidal fracture and a uniform microcrystalline texture. Common worldwide, especially in sedimentary basins and gravel deposits.