sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6.5-7 (Mohs scale); Color: Reddish-brown to pink (due to iron oxide); Luster: Dull or earthy; Crystal structure: Clastic (grainy texture); Cleavage: None (grains are sand particles); Specific gravity: 2.2-2.8

Hardness: 6
Color: Reddish-brown to pink (due to iron oxide)
Luster: Dull or earthy

Identified May 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments, typically in desert, river, or coastal environments. The red hue often indicates formation in terrestrial oxygen-rich environments during the Paleozoic or Mesozoic eras.

Uses & applications

Widely used in construction for flagstones, paving, building facades, and historically for cathedrals and monuments. It is also a source for glass-making sand if high in silica.

Geological facts

The famous Red Rocks Amphitheatre in Colorado is carved from areally extensive red sandstone. It is often called 'brownstone' when used in the historical architecture of New York City and various European cities.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and distinct bedding layers if present. It is commonly found in the American Southwest, the British Isles (Old Red Sandstone), and the Himalayan foothills.