sedimentary

Ferruginous Sandstone

Sandstone (enriched with Iron Oxide)

AI-generated identification · may be incorrect

Hardness: 6-7 (Mohs scale); Color: Brown, rusty orange, dark grey; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 (Mohs scale)
Color: Brown, rusty orange, dark grey
Luster: Dull/Earthy

Identified July 14, 2026More sedimentary →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Brown, rusty orange, dark grey; 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 or rock fragments, with iron oxides (like hematite or goethite) acting as the binding cement. These typically form in river, desert, or marine environments over millions of years.

Uses & applications

Commonly used as a building material, in road construction, or as decorative garden stones. High-iron variants were historically used as low-grade iron ore.

Geological facts

The reddish-brown staining is caused by the oxidation of iron minerals, essentially the same process that causes rust. This stone is often associated with 'ironstones' and can sometimes preserve trace fossils or burrows.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and its characteristic rusty color. It is extremely common in sedimentary basins worldwide. For collectors, it is usually valued for its texture or specific localities.