sedimentary

Red Sandstone

Arenite (with Iron Oxide / Hematite staining)

AI-generated identification · may be incorrect

Hardness: 6-7 on Mohs scale (due to quartz content); Color: Pink to deep reddish-brown; Luster: Dull to earthy; Crystal Structure: Clastic (granular); Cleavage: None (breaks across grains); Specific Gravity: 2.2 - 2.8.

Hardness: 6-7 on Mohs scale (due to quartz content)
Color: Pink to deep reddish-brown
Luster: Dull to earthy

Identified March 23, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains (primarily quartz). The reddish hue is caused by the oxidation of iron minerals (hematite) within the cementing matrix. Often formed in arid terrestrial environments like deserts or river floodplains.

Uses & applications

Extensively used in construction as a building stone (brownstone), flagstone for landscaping, and crushed stone for road base. In the lapidary arts, it is occasionally used for decorative carvings.

Geological facts

Famous structures made of red sandstone include the 'Red Fort' in Delhi and many of the iconic 'Brownstone' buildings in New York City. The staining acts as a record of historical oxygen levels in the atmosphere during deposition.

Field identification & locations

Identify by its gritty, sandpaper-like feel and visible grains. It can be found globally, with massive deposits in the Southwestern United States (Grand Canyon, Sedona) and Scotland. Collectors should look for cross-bedding patterns or ripple marks within the layers.