sedimentary

Rounded sandstone pebble

Clastic sandstone, predominantly quartz (SiO₂) grains in a cementing matrix

AI-generated identification · may be incorrect

Fine- to medium-grained, tan-brown, dull earthy luster, visibly granular surface, and well-rounded edges from abrasion; typical hardness is about 6–7 for quartz grains, with variable bulk hardness and specific gravity around 2.2–2.7. No distinct crystals or cleavage are visible.

Identified August 30, 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; the rounded shape indicates transport in a river, beach, or glacial environment. Its exact geological age cannot be determined from the image.

Uses & applications

Used as aggregate, building stone, paving, and landscaping material; attractive pieces may be collected or used in crafts, but this specimen appears common and non-gem quality.

Geological facts

The brown color likely reflects iron-oxide staining or a ferruginous cement. Surface texture and rounding are consistent with natural weathering and transport rather than a crystal or metallic mineral.

Field identification & locations

Identify sandstone by its gritty texture and sand-sized grains; quartz-rich varieties can scratch glass, while acid reaction suggests calcite cement. Common worldwide in sedimentary basins, riverbeds, beaches, and glacial deposits.