sedimentary

Rounded sandstone pebble

Quartz-rich sandstone (likely arkosic or lithic sandstone)

AI-generated identification · may be incorrect

Fine- to medium-grained, brown/tan, dull to slightly sugary luster, with visible sand grains and scattered pale mineral specks; individual grains are commonly quartz and feldspar. Typical hardness is about 6–7 for quartz grains, but the cemented rock may scratch variably;…

Identified September 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand accumulated, was compacted, and cemented by silica, calcite, or iron oxides, probably during a sedimentary period that cannot be determined from the photograph. Its smooth, flattened shape indicates prolonged stream, beach, or glacial abrasion.

Uses & applications

Common sandstone is used as building stone, paving, landscaping material, and aggregate; this rounded specimen has primarily decorative or educational value.

Geological facts

The brown coloration likely comes from iron-oxide coatings or cement. The surface may show weathered quartz grains, but the photograph does not reveal bedding or fossils.

Field identification & locations

Identify it by gritty texture, visible sand-sized grains, and a lack of crystalline interlocking texture; dilute acid testing may fizz if calcite-cemented. Sandstone occurs widely in sedimentary basins, river gravels, beaches, and glacial deposits.