sedimentary

Likely weathered sandstone or iron-rich shale

Quartz-rich sandstone, possibly ferruginous sandstone; exact identification requires testing

AI-generated identification · may be incorrect

Brown-red, dull to slightly earthy luster, visibly granular and porous with layered/rough fracture; predominantly quartz with clay minerals and iron oxides. Estimated Mohs hardness 6–7 for quartz grains, but the specimen may crumble along bedding.

Identified September 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand or mud accumulated, compacted, and cemented in sedimentary beds; red coloration commonly reflects oxidized iron. Its age cannot be determined from the photograph.

Uses & applications

Used as building stone, paving, aggregate, and decorative material; this small fragment has mainly educational or collector interest.

Geological facts

The rusty color typically indicates hematite or limonite cement. A hand lens can distinguish sandstone’s visible sand grains from the smoother, fissile texture of shale.

Field identification & locations

Common in sedimentary basins worldwide, including the Colorado Plateau, Appalachians, and many continental deposits. Check grain size, bedding, reaction to dilute acid, and whether a steel nail scratches it; the image alone cannot establish a precise identity.