sedimentary
Rounded river pebble, likely weathered sandstone or siltstone
Indeterminate clastic sedimentary rock; likely quartz-rich sandstone/siltstone
AI-generated identification · may be incorrectGray-green, fine-grained, dull to weakly earthy luster, with dark curving bedding or mineral-stain lines. Estimated hardness 5–7 if sandstone (or 3–4 if unusually clay-rich); cleavage absent and specific gravity about 2.2–2.7.
Identified More sedimentary →
Explore Rounded river pebble, likely weathered sandstone or siltstone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray-green, fine-grained, dull to weakly earthy luster, with dark curving bedding or mineral-stain lines. Estimated hardness 5–7 if sandstone (or 3–4 if unusually clay-rich); cleavage absent and specific gravity about 2.2–2.7.
Formation & geological history
Originally lithified from compacted sand or silt, then rounded and smoothed by water abrasion; its exact geological age and formation locality cannot be determined from the photograph.
Uses & applications
Typically a common collecting specimen, decorative pebble, or craft material; not generally suitable for jewelry or industrial use unless part of a distinctive local formation.
Geological facts
The dark lines may represent bedding, iron/manganese staining, or weathered fractures rather than fossils. The smooth oval shape strongly indicates transport in a stream, river, or wave environment.
Field identification & locations
Look for a gritty texture and visible sand grains to confirm sandstone; a very smooth, powdery surface suggests siltstone or mudstone. Common in river gravels and beaches worldwide; a hand lens and streak/hardness tests would improve identification.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary