sedimentary
Concretion (Sandstone)
Sandstone Concretion
AI-generated identification · may be incorrectHardness: 6-7 (Mohs scale), Color: tan/brown/grey, Luster: dull/earthy, Structure: spherical/ellipsoid, Cleavage: none, Specific Gravity: 2.5-2.8
Identified More sedimentary →
Explore Concretion (Sandstone) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs scale), Color: tan/brown/grey, Luster: dull/earthy, Structure: spherical/ellipsoid, Cleavage: none, Specific Gravity: 2.5-2.8
Formation & geological history
Formed by the precipitation of mineral cement within the spaces between sediment grains, often around a nucleus like a leaf or shell. Commonly found in sedimentary rock layers like sandstone or shale.
Uses & applications
Primarily used as decorative items, educational specimens, or garden ornaments; some types (like ironstone) can be an ore source.
Geological facts
Commonly known as Moquie marbles or cannonballs when perfectly spherical. They can grow to several meters in diameter or be as small as a pebble.
Field identification & locations
Identify by its distinct spherical shape contrasting with the surrounding sedimentary bedding. Commonly found in eroding cliffs or streambeds.
More like this
Other sedimentary specimens
Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion
Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image
fossil
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary