Red Sandstone

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Red, reddish-brown, maroon; Luster: Dull to earthy; Crystal structure: Clastic (grains); Cleavage: None; Specific gravity: 2.2-2.8

Formation & Geological History

Formed by the accumulation of sand-sized mineral particles or rock fragments, cemented together by silica or iron oxide. The red color indicates formation in an oxygen-rich terrestrial environment, often during the Permian or Triassic periods.

Uses & Applications

Extensively used as a building material, decorative stone in landscaping, for making grindstones, and sometimes as an aquifer for groundwater or a reservoir for petroleum.

Geological Facts

The famous 'Red Rocks' of Colorado and the ancient city of Petra in Jordan are both carved from or composed of red sandstone. The color is caused by the oxidation of iron minerals like hematite within the matrix.

Field Identification & Locations

Identify in the field by its gritty texture (like sandpaper) and lack of visible layering in some hand specimens. Found worldwide in sedimentary basins, particularly in the Southwestern United States and the United Kingdom.

Identified on: 5/3/2026

Mode: Standard