sedimentary

Red Sandstone

Quartz Arenite (with Iron Oxide)

Hardness: 6-7 (individual grains); Color: Red, rust-orange; Luster: Dull, earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 (individual grains)
Color: Red, rust-orange
Luster: Dull, earthy

Identified May 24, 2026More sedimentary →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6-7 (individual grains); Color: Red, rust-orange; Luster: Dull, earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation of sand-sized mineral grains, primarily quartz, which are cemented by minerals like silica or iron oxide. The red color suggests deposition in an oxygen-rich terrestrial environment, often dating back to the Triassic or Permian periods.

Uses & applications

Widely used in construction for building stone, paving, and decorative garden rock. In powdered form, it can be used for manufacturing glass or as an abrasive.

Geological facts

The vibrant red color is caused by the oxidation of iron minerals (hematite trapping grains), similar to how metal rusts. Famous formations include the Grand Canyon and the Red Rocks of Colorado.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and distinct red-to-brown layering. Commonly found in desert regions, ancient riverbeds, and sedimentary basins. Test for hardness to distinguish from softer claystones.