sedimentary
Red Sandstone (Siltstone pebble)
Arenite / Siltstone (Silicon dioxide based with hematite impurities)
Hardness: 6-7 Mohs; Color: Dull reddish-purple to maroon; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.3-2.6
- Hardness
- 6-7 Mohs
- Color
- Dull reddish-purple to maroon
- Luster
- Dull/Earthy
Identified More sedimentary →
Explore Red Sandstone (Siltstone pebble) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 Mohs; Color: Dull reddish-purple to maroon; Luster: Dull/Earthy; Structure: Clastic; Cleavage: None; Specific Gravity: 2.3-2.6
Formation & geological history
Formed through the accumulation, compaction, and cementation of sand-sized mineral particles or rock fragments. The red/purple hue indicates the presence of iron oxide (hematite) during the lithification process, often in arid or fluvial environments.
Uses & applications
Common pebbles like this are used in landscaping, decorative stone mulch, and as natural abrasives. High-quality sandstone is a major building and paving material.
Geological facts
The color suggests it may be part of the 'Old Red Sandstone' or similar formations which date back to the Devonian period (approx. 400 million years ago). Water-worn pebbles like this are often found in riverbeds or on glacial till plains.
Field identification & locations
Identify in the field by its gritty texture and lack of visible crystals. It will not react with acid (unlike limestone). Commonly found in regions with ancient sedimentary basins or glacial deposits.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Shale
Shale (clastic sedimentary rock)
sedimentary
Brown Sandstone (River Rock)
Arenite
sedimentary
Shale
Argillaceous sedimentary rock
sedimentary