sedimentary

Weathered sandstone cobble

Quartz-rich sandstone, primarily SiO₂ with clay/iron-oxide cement

AI-generated identification · may be incorrect

Typically Mohs 6–7 for quartz grains but weaker overall; pinkish-red, fine to medium grained, dull to earthy luster, porous, and non-cleavable. The rounded shape and surface pits indicate prolonged weathering and abrasion.

Identified August 12, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand was deposited, compacted, and cemented, commonly in river, dune, or shallow-marine environments; its exact geological age cannot be determined from the image. Iron oxides likely produced the reddish coloration.

Uses & applications

Used as aggregate, building stone, paving material, and landscaping rock; attractive pieces may be collected but are generally low value.

Geological facts

The specimen appears strongly weathered, with possible small cavities or pebble impressions; it may also be a ferruginous sandstone or weathered arkosic sandstone rather than pure quartz sandstone.

Field identification & locations

Identify it by visible sand-sized grains, granular texture, pink-red iron staining, and lack of crystalline cleavage; common in sedimentary terrains, riverbeds, glacial deposits, and construction fill.