sedimentary

Weathered sandstone or arkose

Quartz–feldspar clastic sedimentary rock; likely arkosic sandstone

AI-generated identification · may be incorrect

Typically Mohs hardness 6–7 for quartz grains, with variable cement hardness; tan, orange, and reddish-brown color, gritty texture, and earthy to dull luster. Visible coarse grains and iron-oxide staining suggest quartz, feldspar, and hematite/goethite cement; bedding or cleavage is absent.

Identified August 31, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from deposited, compacted, and cemented sand, probably in a river, alluvial-fan, or desert setting. The orange-red coloration developed through oxidation of iron-bearing minerals; exact age cannot be determined from the photograph.

Uses & applications

Used as building stone, landscaping aggregate, and occasionally decorative material; coarse or friable examples have limited commercial value.

Geological facts

Arkose contains abundant feldspar—commonly over about 25%—and often forms near rapidly eroding granitic source rocks. Iron oxides can produce vivid rusty surfaces during weathering.

Field identification & locations

Identify it by its gritty feel, visible sand-sized grains, weak layering, and rusty iron staining; a glassy scratch test may show quartz grains scratching glass. Common worldwide, especially near granitic uplands and arid sedimentary basins.