sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6-7 (on Mohs scale); Color: Red, reddish-brown; Luster: Dull, earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 (on Mohs scale)
Color: Red, reddish-brown
Luster: Dull, earthy

Identified April 13, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (on Mohs scale); Color: Red, reddish-brown; Luster: Dull, earthy; Crystal structure: Clastic (sand-sized grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of mineral particles or rock fragments (clasts). The red color indicates oxidation of iron (hematite) during or after deposition in terrestrial environments like deserts or floodplains.

Uses & applications

Used primarily in construction for building facades, road base, and landscaping stone. It is also used as an abrasive in some industrial sandblasting processes.

Geological facts

Many famous landmarks are made of red sandstone, including the Red Fort in India and Petra in Jordan. It is often referred to as 'Old Red Sandstone' when dating back to the Devonian period.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and distinct brick-red color. It is commonly found in basins or former desert regions. For collectors, look for cross-bedding patterns which indicate ancient wind or water flow.