sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6-7 Mohs; Color: reddish-brown due to iron oxide (hematite); Luster: dull to earthy; Crystal structure: clastic (sand-sized grains); Cleavage: none; Specific gravity: 2.2-2.8.

Hardness: 6-7 Mohs
Color: reddish-brown due to iron oxide (hematite)
Luster: dull to earthy

Identified April 6, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: reddish-brown due to iron oxide (hematite); Luster: dull to earthy; Crystal structure: clastic (sand-sized grains); Cleavage: none; Specific gravity: 2.2-2.8.

Formation & geological history

Formed from the accumulation of sand-sized mineral particles or rock fragments, cemented together by silica, calcium carbonate, or iron oxide. The red color indicates formation in an oxidizing terrestrial environment, often during the Paleozoic or Mesozoic eras.

Uses & applications

Widely used as a building material, paving stone, and for decorative masonry. Historically significant for temples and government buildings. Finely ground sandstone is sometimes used as an abrasive.

Geological facts

Red sandstone is the primary material of many famous landmarks, including the 'Red Rocks' of Colorado, the Grand Canyon walls, and the Red Fort in India. It is a major reservoir rock for groundwater and petroleum.

Field identification & locations

Identified by its gritty sandpaper feel and visible sand grains. Common in arid environments or ancient riverbeds. To identify in the field, check for bedding planes and use a hand lens to see mineral grains.