sedimentary

Sandstone (Ferruginous)

Arenite (Fe2O3 rich)

Hardness: 6-7 (Mohs); Color: Reddish-brown, tan, or ochre; Luster: Dull/Earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 (Mohs)
Color: Reddish-brown, tan, or ochre
Luster: Dull/Earthy

Identified April 2, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs); Color: Reddish-brown, tan, or ochre; Luster: Dull/Earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific Gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized silicate grains. The reddish hue indicates the presence of iron oxide (hematite) during the lithification process. Common in ancient river beds, deserts, and marine environments.

Uses & applications

Used widely in construction for building stone and paving. Occasionally used for sharpening tools (whetstones) or as a source of silica in glass manufacturing.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. The 'red beds' seen in many national parks are specific examples of ferruginous sandstone where iron minerals have oxidized.

Field identification & locations

Identify in the field by its gritty 'sandpaper' feel and visible layers of stratification. It is extremely common in the Colorado Plateau and Appalachian regions of North America.