sedimentary

Sandstone (specifically Red Sandstone)

Arenite (SiO2 with Iron Oxide)

Hardness: 6-7 on Mohs scale; Color: Reddish-brown, tan, or pink due to iron oxide; Luster: Dull or earthy; Crystal structure: Clastic (grainy texture); Cleavage: None, breaks across grains; Specific gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale
Color: Reddish-brown, tan, or pink due to iron oxide
Luster: Dull or earthy

Identified April 19, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the accumulation and cementation of mineral particles or rock fragments (sand) over millions of years. This often occurs in desert or river bed environments. Can range from the Precambrian to Cenozoic eras.

Uses & applications

Extensively used as a building material, paving stone, decorative garden stones, and as a source of silica for glass manufacturing. Highly valued in architecture for its durability and aesthetic appeal.

Geological facts

Red sandstone is what gives the famous landscapes of the American Southwest, such as the Grand Canyon and Zion National Park, their iconic colors. It is also the primary material used for the 'Brownstone' houses in New York City.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel and visible grains. Often displays bedding planes or layers. Frequently found in regions with ancient sedimentary basins or dry highland environments.

Other sedimentary specimens

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Sandstone or Siltstone

Arenite (if sandstone)

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Chert Breccia

Brecciated Chert (Microcrystalline Silica)

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Sandstone

Arenite (primarily SiO2)

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Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

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Shale or Slaty Mudstone

Argillaceous sedimentary rock

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Sandstone

Arenite

sedimentary