sedimentary
Sandstone Concretion
Sedimentary Clastic Rock (Silicate-rich)
Hardness: 6-7 (Mohs scale), Color: Tan to light brown, Luster: Dull/Earthy, Crystal Structure: Granular/Clastic, Specific Gravity: 2.3-2.6
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs scale), Color: Tan to light brown, Luster: Dull/Earthy, Crystal Structure: Granular/Clastic, Specific Gravity: 2.3-2.6
Formation & geological history
Formed by the precipitation of mineral cement within the spaces between sediment grains. These often form around a nucleus such as a leaf, shell, or bone during diagenesis in sedimentary basins.
Uses & applications
Used primarily as decorative garden stones, educational geological specimens, and occasionally in crushed form for construction aggregate.
Geological facts
Concretions are often mistaken for fossils, eggs, or man-made artifacts due to their unusual and sometimes organic-looking shapes. They can range from millimeters to several meters in size.
Field identification & locations
Identify by looking for rounded or curiously shaped nodules that differ in hardness or color from the surrounding host rock. Commonly found in eroded sandstone cliffs or riverbeds.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary