sedimentary
Limestone
CaCO3 (Calcium Carbonate)
AI-generated identification · may be incorrectHardness: 3-4 (Mohs scale), Color: light grey to tan, Luster: dull to earthy, Crystal structure: Trigonal (microcrystalline), Cleavage: none, Specific gravity: 2.3-2.7
Identified More sedimentary →
Explore Limestone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3-4 (Mohs scale), Color: light grey to tan, Luster: dull to earthy, Crystal structure: Trigonal (microcrystalline), Cleavage: none, Specific gravity: 2.3-2.7
Formation & geological history
Formed in warm, shallow marine environments from the accumulation of shell, coral, algal, and fecal debris. This specimen appears water-worn, likely found in a river or coastal area.
Uses & applications
Used primarily in construction as aggregate, for making cement, as a flux in steel production, and as an agricultural soil conditioner.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It is highly susceptible to acid rain, which creates caves and sinkholes over geological time.
Field identification & locations
Can be identified by a 'fizz' test (effervescence) when a small drop of diluted hydrochloric acid or vinegar is applied. Commonly found in ancient sea beds and riverbanks.
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