sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Mohs hardness: 6 to 7; Color: Red, orangish-brown; Luster: Dull/Earthy; Crystal structure: Clastic (grains of quartz); Cleavage: None (breaks across grains); Specific gravity: 2.2 to 2.8.

Hardness: 6 to 7
Color: Red, orangish-brown
Luster: Dull/Earthy

Identified June 5, 2026More sedimentary →

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Physical properties

Mohs hardness: 6 to 7; Color: Red, orangish-brown; Luster: Dull/Earthy; Crystal structure: Clastic (grains of quartz); Cleavage: None (breaks across grains); Specific gravity: 2.2 to 2.8.

Formation & geological history

Formed by the accumulation and lithification of sand-sized grains, typically in desert or river environments. The red color comes from iron oxide (hematite) coating the grains. Typical age ranges from the Precambrian to Cenozoic.

Uses & applications

Extensively used in construction, as dimension stone for buildings, paving, and decorative garden landscaping. Industrially, it can be a source of silica.

Geological facts

The red color is essentially 'rusting' of iron minerals within the rock. Famous examples include the 'Red Rocks' of Colorado and the sandstone cliffs of the American Southwest.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and visible sand grains. Commonly found in arid regions or ancient basins. Collectors look for unique banding or fossil inclusions.