sedimentary

Red Sandstone (Iron-Rich)

Arenite (Fe2O3)

Hardness: 6-7 Mohs (quartz-based); Color: Rusty orange/red; Luster: Dull/Earthy; Crystal structure: Granular (clastic); Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 Mohs (quartz-based)
Color: Rusty orange/red
Luster: Dull/Earthy

Identified March 29, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs (quartz-based); Color: Rusty orange/red; Luster: Dull/Earthy; Crystal structure: Granular (clastic); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains. The red color is caused by the oxidation of iron minerals (hematite) during lithification, typically in arid terrestrial environments like deserts or floodplains.

Uses & applications

Used primarily in building construction as dimension stone, for road metal, and as a decorative landscaping rock. High-purity silica sandstone is used in glassmaking.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The iconic 'Red Rocks' of the American Southwest, such as the Grand Canyon and Zion National Park, are composed largely of variations of this material.

Field identification & locations

Identify in the field by its gritty, sandpaper-like texture and visible sand grains. It is commonly found in sedimentary basins and along riverbeds. For collectors, look for cross-bedding patterns or ripple marks.