sedimentary

Sandstone (Ferruginous)

Arenite with Iron-Oxide Cement (primarily SiO2 with Fe2O3/FeOOH)

Hardness: 6-7 on Mohs scale (due to quartz content); Color: Tan, brown, or rusty orange (iron staining); Luster: Dull/Earthy; Crystal structure: Clastic/Granular; Cleavage: None, breaks across grains.

Hardness: 6-7 on Mohs scale (due to quartz content)
Color: Tan, brown, or rusty orange (iron staining)
Luster: Dull/Earthy

Identified April 6, 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 distinct orange/brown coloration comes from the oxidation of iron-bearing minerals during lithification or weathering. They are found in ancient riverbeds, deserts, or marine environments.

Uses & applications

Commonly used in construction as a building material, paving stone, or decorative landscaping rock. High-purity sandstones are crushed for industrial glass making.

Geological facts

Sandstone accounts for approximately 20% of all sedimentary rocks on Earth. The rusted orange color is essentially the same chemical process as metal rusting, where iron minerals react with oxygen and water.

Field identification & locations

Identify in the field by its gritty, sandpaper-like texture. Look for layering (bedding planes) and check if it can scratch glass. It is commonly found in sedimentary basins and canyon systems.

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Sandstone (Quartz-rich)

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Sandstone (with man-made markings)

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