sedimentary

Red Sandstone

Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)

AI-generated identification · may be incorrect

Hardness: 6-7 (Quartz grains) but often friable; Color: Reddish-brown, terracotta, or pink; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None (fractures around grains); Specific Gravity: 2.2 - 2.8

Hardness: 6-7 (Quartz grains) but often friable
Color: Reddish-brown, terracotta, or pink
Luster: Dull/Earthy

Identified March 30, 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. The red color indicates formation in an oxygen-rich environment where iron minerals oxidized (rusted). Often found in ancient desert dunes or river delta systems ranging from Paleozoic to Mesozoic eras.

Uses & applications

Widely used as a building material and decorative stone (brownstone). Used in landscaping, glass manufacturing (if high purity silica), and as an abrasive in industrial applications.

Geological facts

Famous red sandstone formations include the Grand Canyon's layers, the 'Red Rocks' of Colorado, and the ancient city of Petra in Jordan, which was carved directly into red sandstone cliffs.

Field identification & locations

Identify in the field by its gritty, sandpaper-like feel and visible layering (bedding). It will not fizz with acid unless it has a rare calcite cement. Commonly found in arid regions or uplifted sedimentary basins.