Sandstone (specifically Red Sandstone)

Physical Properties

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

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.

Identified on: 4/19/2026

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