sedimentary

Sandstone with Iron Staining

Arenite (SiO2 with Fe-oxide coatings)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Tan, brownish-gold, and reddish-brown; Luster: Dull/Earthy; Structure: Clastic; Texture: Gritty/Grainy; Specific Gravity: 2.2-2.8

Hardness: 6
Color: Tan, brownish-gold, and reddish-brown
Luster: Dull/Earthy

Identified July 15, 2026More sedimentary →

Explore Sandstone with Iron Staining in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 6.5-7 (Mohs); Color: Tan, brownish-gold, and reddish-brown; Luster: Dull/Earthy; Structure: Clastic; Texture: Gritty/Grainy; Specific Gravity: 2.2-2.8

Formation & geological history

Formed from the accumulation of sand-sized mineral particles or rock fragments, cemented together by silica or minerals like limonite and hematite. The reddish-brown patches are evidence of iron oxidation (chemical weathering).

Uses & applications

Primarily used as a building material, road base, or for architectural stone; also serves as a critical reservoir for water or petroleum in geological formations.

Geological facts

Sandstone represents about 20-25% of all sedimentary rocks on Earth. The 'rusty' brown patches on this specimen are often called 'desert varnish' or iron staining, occurring when iron-rich minerals react with oxygen.

Field identification & locations

Identify in the field by its sandpaper-like feel and visible grains. It is often found in desert environments, riverbeds, and sedimentary basins worldwide. This specific specimen shows weathering rinds.