sedimentary
Sandstone or Siltstone
Arenite or Siltstone
Reddish, brownish, or orange color due to iron oxides. Granular texture, fine to medium grain size. Hardness varies depending on the cement, typically around 6-7 if quartz-rich.
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Physical properties
Reddish, brownish, or orange color due to iron oxides. Granular texture, fine to medium grain size. Hardness varies depending on the cement, typically around 6-7 if quartz-rich.
Formation & geological history
Formed by the accumulation and cementation of sand-sized or silt-sized particles (often quartz and feldspar) in environments like rivers, deserts, or shallow seas. Often stained red by iron oxide (hematite).
Uses & applications
Historically used in construction, as flagstone, or for decorative landscaping.
Geological facts
The reddish color is very common in sedimentary rocks deposited in oxygen-rich terrestrial environments.
Field identification & locations
Identified by its gritty feel (if sandstone) or smooth but earthy feel (if siltstone). Commonly found worldwide in sedimentary basins.
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