sedimentary

Sandstone (Ferruginous)

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Brown, reddish-brown, tan; Luster: Dull/Earthy; Structure: Clastic, fine-to-medium grained; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: Brown, reddish-brown, tan
Luster: Dull/Earthy

Identified June 28, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Brown, reddish-brown, tan; Luster: Dull/Earthy; Structure: Clastic, fine-to-medium grained; Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains, primarily quartz. The brown/red hue suggests iron-rich (ferruginous) cementation, often occurring in riverbeds, deserts, or coastal environments over millions of years.

Uses & applications

Commonly used as a building material, grit for sharpening, paving stones, and in the manufacturing of glass. Iron-rich varieties are occasionally studied for geochemical properties.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The coloration is often due to hematite or goethite acting as a binding agent between quartz grains.

Field identification & locations

Identify by its gritty, sandpaper-like feel and visible pores. In the field, look for layering (bedding) and test the hardness; it should easily scratch glass if it is quartz-based.