sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness: 3 (Mohs Scale), Color: tan/light gray, Luster: dull to earthy, Crystal Structure: Hexagonal (as calcite), Cleavage: Perfect rhombohedral in crystal form, Specific Gravity: 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 (Mohs Scale), Color: tan/light gray, Luster: dull to earthy, Crystal Structure: Hexagonal (as calcite), Cleavage: Perfect rhombohedral in crystal form, Specific Gravity: 2.7
Formation & geological history
Formed primarily from the accumulation of shell, coral, algal, and fecal debris in warm, shallow marine waters. Can also form through chemical precipitation from lakewater or ocean water.
Uses & applications
Used extensively in construction (road base, concrete, mortar), agriculture to neutralize soil acidity, and as a raw material for cement.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary rock type found in 'Karst' topography, which is known for caves and sinkholes.
Field identification & locations
Identify in the field using a drop of weak acid (like vinegar); it will effervesce (fizz). Commonly found in areas that were once prehistoric seafloors.
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