sedimentary

Iron-rich sandstone or weathered ironstone cobble

Ferruginous sandstone; primarily quartz (SiO₂) cemented or stained by iron oxides such as hematite and goethite

AI-generated identification · may be incorrect

Hardness about 5–7 Mohs; reddish-brown, dull to earthy luster, fine-grained and massive, with no obvious cleavage. The rounded shape and abraded surface indicate water or sediment transport.

Identified August 26, 2026More sedimentary →

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Physical properties

Hardness about 5–7 Mohs; reddish-brown, dull to earthy luster, fine-grained and massive, with no obvious cleavage. The rounded shape and abraded surface indicate water or sediment transport.

Formation & geological history

Likely formed when quartz-rich sand was cemented and strongly stained by oxidized iron, then weathered and rounded in a stream, beach, or glacial environment. Exact age cannot be determined from the photograph.

Uses & applications

Used locally as durable aggregate, landscaping stone, building stone, or pigment source; generally has little jewelry value.

Geological facts

Iron oxides produce the characteristic red, orange, and brown coloration. The specimen may also be a weathered ironstone or hematite-bearing conglomeratic rock rather than pure sandstone.

Field identification & locations

Common in sedimentary basins, streambeds, beaches, and glacial deposits worldwide. A hand lens should reveal sand-sized quartz grains; a streak test may show reddish-brown powder, and a steel nail may scratch softer weathered areas.