sedimentary
Ferruginous Sandstone
Arenite with Hematite/Goethite cement
Hardness: 6-7 (approx); Color: Dark reddish-brown to maroon; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.5-3.0
- Hardness
- 6-7 (approx)
- Color
- Dark reddish-brown to maroon
- Luster
- Dull/Earthy
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Physical properties
Hardness: 6-7 (approx); Color: Dark reddish-brown to maroon; Luster: Dull/Earthy; Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.5-3.0
Formation & geological history
Formation results from the deposition of sand-sized grains (mostly quartz) which are later cemented together by iron oxides (hematite or limonite) precipitated from groundwater. Commonly found in terrestrial or shallow marine environments.
Uses & applications
Used primarily as low-grade building stone, landscaping rock, or in some cases as a minor source of iron ore if the concentration is high enough.
Geological facts
The deep red color is caused by the oxidation of iron, essentially 'rust' within the rock. These rocks are often used to interpret past environmental conditions and water table history.
Field identification & locations
Identify by its gritty texture (sandpaper feel) and the characteristic reddish-brown streak it leaves on a porcelain plate. Common in regions with high iron content in the soil or ancient sea beds.
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