sedimentary

Red sandstone or iron-stained chert

Likely quartz-rich sandstone (SiO₂) or microcrystalline quartz/chert with hematite

AI-generated identification · may be incorrect

Reddish-brown, dull to subtly earthy luster, massive and fine-grained, with dark iron- or manganese-rich patches; estimated Mohs hardness 6–7. The rounded shape suggests natural abrasion or tumbled handling, but texture is insufficient for certain identification.

Identified September 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed from silica-rich sediment cemented during burial, with red coloration from hematite oxidation; alternatively it may be chemically precipitated chert. Age cannot be determined from the photograph; such materials range from Precambrian to modern sedimentary formations.

Uses & applications

Common sandstone is used as building stone, aggregate, paving, and decorative material; chert is used for tools, abrasives, and collecting. This specimen has modest display value unless provenance or unusual banding is established.

Geological facts

Iron oxides commonly produce red, orange, and brown coloration in sedimentary rocks. A freshly broken surface and a hardness or streak test would distinguish sandstone from chert more reliably.

Field identification & locations

Look for visible sand grains and a gritty fracture for sandstone; chert is smoother, waxy, and conchoidally fractured, and typically scratches glass. Common worldwide, especially in arid continental basins and ancient sedimentary terrains.