sedimentary

Weathered red sandstone cobble

Quartz-rich sandstone, likely ferruginous arkose or litharenite

AI-generated identification · may be incorrect

Hardness about 6–7 for quartz grains, with a dull earthy to slightly sandy luster; reddish-brown coloration comes from iron oxides, while the pale surface is weathered cement or alteration. The rounded shape indicates natural abrasion, and visible granular texture suggests clastic sediment rather than a crystal-rich ig…

Identified September 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand-sized quartz and feldspar or rock fragments were deposited, compacted, and cemented, commonly in river, floodplain, dune, or shallow-marine settings. Its precise geological age cannot be determined from the photograph; rounding likely occurred in a stream or gravel deposit.

Uses & applications

Used as building and landscaping stone, aggregate, and occasionally as a decorative specimen; it has little jewelry value unless unusually colorful or patterned.

Geological facts

Iron-oxide coatings commonly produce red, orange, and brown sandstone. Weathering can preferentially remove softer cement, creating pits and a roughened surface.

Field identification & locations

Identify it by its gritty granular texture, muted red color, lack of visible interlocking crystals, and possible sand grains that can scratch glass. Common in sedimentary basins and stream gravels worldwide.