sedimentary

Sandstone (River Cobble / Pebble)

Sedimentary Rock (Quartz Sandstone / Arenite)

Hardness: 6-7 (Mohs scale), Color: Earthy yellowish-brown to tan, Luster: Dull to earthy, Texture: Fine to medium-grained, feel like sandpaper, Features: Porous with small solution cavities or weathered pore spaces

Identified July 24, 2026More sedimentary →

Explore Sandstone (River Cobble / Pebble) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed by the compaction and cementation of mineral particles or rock fragments, predominantly quartz and feldspar, usually deposited in riverbeds, lakes, or coastal environments over millions of years. This specimen shows significant water-rounding and weathering.

Uses & applications

Used extensively in construction as building stone, paving, and aggregate. Also collected as natural decorative pebbles or river stones.

Geological facts

Sandstone is one of the most common sedimentary rocks on Earth, making up about 20% of all sedimentary rocks. The cavities in this specimen are likely caused by dissolved softer inclusions or differential weathering.

Field identification & locations

Identified by its grainy, sand-like texture, rounded river-worn shape, and earthy color. Commonly found along riverbeds, lakeshores, beaches, and sedimentary rock formations worldwide. Collector value is minimal due to extreme abundance.

Other sedimentary specimens

See all

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Sedimentary Sandstone

Arenite (Sedimentary Rock)

sedimentary

Fossiliferous Concretion

Septarian Concretion containing Brachiopods/Crinoids

fossil

Shale

Shale (clastic sedimentary rock)

sedimentary

Shale

Argillaceous sedimentary rock

sedimentary

Mudstone

Argillite / Siliciclastic sedimentary rock

sedimentary