sedimentary

Red Sandstone

Arenite (Ferruginous Sandstone)

Hardness: 6-7 (Mohs scale for quartz grains); Color: Reddish-brown to terracotta; Luster: Dull, earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Texture: Gritty, sandpaper-like.

Hardness: 6-7 (Mohs scale for quartz grains)
Color: Reddish-brown to terracotta
Luster: Dull, earthy

Identified July 2, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale for quartz grains); Color: Reddish-brown to terracotta; Luster: Dull, earthy; Crystal structure: Clastic (sand grains); Cleavage: None; Texture: Gritty, sandpaper-like.

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral particles or rock fragments. The red color is due to the presence of iron oxide (hematite) coating the grains. Often found in ancient riverbeds, deserts, and floodplains.

Uses & applications

Extensively used as a building material, pavement stone, and for decorative landscape architecture. Historically popular in monuments and cathedrals because of its distinctive color.

Geological facts

The famous 'Red Rocks' of the American Southwest and the 'Old Red Sandstone' of Great Britain are iconic examples. It often preserves cross-bedding structures that indicate the direction of ancient wind or water currents.

Field identification & locations

Identified by its gritty feel and red streak. It is commonly found in sedimentary basins and arid mountain regions. Collectors should look for unique weathering patterns or fossil inclusions.