sedimentary

Ferruginous Sandstone (Gozzan/Ironstone)

Arenite with Limonite/Goethite cement (FeO(OH)·nH2O)

Hardness: 5-6 (Mohs); Color: Rusty brown, reddish-orange to dark grey; Luster: Dull, earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.5-3.5 (dense due to iron content).

Hardness: 5-6 (Mohs)
Color: Rusty brown, reddish-orange to dark grey
Luster: Dull, earthy

Identified March 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via the lithification of sand particles where iron-rich groundwater precipitates iron oxides (limonite or hematite) as a cementing agent. Often found in weathered outcrops or as cap-rock over older geological formations.

Uses & applications

Primarily used as low-grade iron ore historically; currently used in construction as road base, decorative landscaping stones, and as an indicator for mineral prospecting (gossans).

Geological facts

This rock is often mistaken for a meteorite due to its weight and dark, weathered 'crust,' but its granular texture and orange iron-oxide staining confirm its terrestrial, sedimentary origin.

Field identification & locations

Identify by its 'rusty' appearance, weight (heavier than normal sandstone), and lack of magnetic attraction (unless magnetite is present). Commonly found in the American Midwest and Appalachian regions.

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