sedimentary

Sandstone

Arenite (predominantly SiO2)

Hardness: 6-7 Mohs; Color: Tan, beige, or yellowish-brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Specific Gravity: 2.2-2.8. Feels gritty like sandpaper.

Hardness: 6-7 Mohs
Color: Tan, beige, or yellowish-brown
Luster: Dull/Earthy

Identified July 20, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, beige, or yellowish-brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Specific Gravity: 2.2-2.8. Feels gritty like sandpaper.

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (clasts) the size of sand. These typically deposit in riverbeds, deserts, or marine environments over millions of years.

Uses & applications

Commonly used as a construction material, for grindstones, for paving, and in glass manufacturing if the quartz content is high enough.

Geological facts

Sandstone can vary greatly in color depending on the impurities; for example, iron oxides create red and orange hues. It is one of the most common sedimentary rocks on Earth.

Field identification & locations

Identify by its gritty texture and visible grains. Often found in layered formations or as rounded river stones like this specimen. Can be tested with a drop of vinegar (if it fizzes, it contains calcium carbonate cement).