sedimentary
Siltstone Pebble
Siltstone (composed of microscopic quartz and clay minerals)
Hardness: 3-5 (Mohs scale); Color: Brownish-grey to olive-green; Luster: Dull/Earthy; Texture: Fine-grained, gritty feeling on teeth; Structure: Clastic
- Hardness
- 3-5 (Mohs scale)
- Color
- Brownish-grey to olive-green
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-5 (Mohs scale); Color: Brownish-grey to olive-green; Luster: Dull/Earthy; Texture: Fine-grained, gritty feeling on teeth; Structure: Clastic
Formation & geological history
Formed from the compaction and cementation of silt-sized particles in low-energy environments like river floodplains or lake beds. This specimen has been rounded and smoothed by water erosion.
Uses & applications
Used primarily as road base, construction fill, or decorative river rock in landscaping.
Geological facts
Siltstone is intermediate between sandstone and shale; it has smaller grains than sandstone but lacks the fissility (layer-splitting property) of shale.
Field identification & locations
Commonly found in riverbeds and glacial deposits. Identification is made by its smooth water-worn surface and a grain size that is too fine to see with the naked eye but feels abrasive.
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