sedimentary
Ferruginous Sandstone (with Laterite)
Ferruginous Arenite (FeO(OH)·nH2O)
Hardness: 6-7 (on Mohs scale for quartz grains); Color: Reddish-brown, tan, and grey; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.5-3.0
- Hardness
- 6-7 (on Mohs scale for quartz grains)
- Color
- Reddish-brown, tan, and grey
- Luster
- Dull/Earthy
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Physical properties
Hardness: 6-7 (on Mohs scale for quartz grains); Color: Reddish-brown, tan, and grey; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.5-3.0
Formation & geological history
Formed through the accumulation of sand grains cemented together by iron oxides (limonite or hematite) in oxidizing environments. Often found in tropical regions where intense weathering (laterization) occurs.
Uses & applications
Used primarily in local construction as road base, decorative landscaping stone, and occasionally as a low-grade iron ore source in historical contexts.
Geological facts
This material is often an indicator of fluctuating water tables. Laterite soils and rocks cover about 33% of the world's land area, predominantly in the tropics.
Field identification & locations
Identified by its gritty texture and characteristic rust-red or dark brown staining. Look for it in areas with highly weathered soil. It will not react with HCl unless it contains carbonate cement.
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