sedimentary
Red Sandstone
Sedimentary Arenite / Quartzose Sandstone
Hardness: 6 to 7 on the Mohs scale (due to quartz grains); Color: Red, reddish-brown, or rust-colored due to iron oxide (hematite or goethite) cement; Luster: Dull to vitreous; Crystal structure: Clastic texture composed of sand-sized mineral grains or rock fragments, primarily quartz;…
- Hardness
- 6 to 7 on the Mohs scale (due to quartz grains)
- Luster
- Dull to vitreous
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Physical properties
Hardness: 6 to 7 on the Mohs scale (due to quartz grains); Color: Red, reddish-brown, or rust-colored due to iron oxide (hematite or goethite) cement; Luster: Dull to vitreous; Crystal structure: Clastic texture composed of sand-sized mineral grains or rock fragments, primarily quartz; Cleavage: None, breaks across grains; Specific Gravity: 2.2 to 2.8.
Formation & geological history
Formed through the accumulation, compaction, and cementation (lithification) of sand-sized mineral particles, most commonly quartz and feldspar, often in desert, beach, or river environments over millions of years. The distinctive red color typically indicates terrestrial (desert or floodplain) deposition where iron oxides coated the grains in an oxidizing environment.
Uses & applications
Widely used as a dimensional building stone, for paving, landscaping, monuments, and historically for constructing castles, cathedrals, and homes.
Geological facts
Many famous geological monuments, such as the grand arches of Utah, the rock-cut city of Petra in Jordan, and Ayers Rock (Uluru) in Australia, are composed of massive sandstone formations.
Field identification & locations
Easily identified by its gritty, sandpaper-like texture, visible sand grains, and often distinct bedding planes or color banding. Common globally wherever ancient deserts, riverbeds, or shallow seas once existed.
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