sedimentary
Limestone
Calcium carbonate (CaCO3)
Hardness of 3 on the Mohs scale, typically white, gray, or tan in color, dull to sub-earthy luster, fine-grained to coarse crystal structure, exhibits good cleavage in three directions (rhombohedral), and specific gravity ranging from 2.7 to 2.9.
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 of 3 on the Mohs scale, typically white, gray, or tan in color, dull to sub-earthy luster, fine-grained to coarse crystal structure, exhibits good cleavage in three directions (rhombohedral), and specific gravity ranging from 2.7 to 2.9.
Formation & geological history
Formed through the accumulation of organic remains such as shells, coral, and algal debris, or through the chemical precipitation of calcium carbonate from water in shallow marine environments over millions of years.
Uses & applications
Widely used in the manufacturing of cement and lime, as a building material, crushed stone for road base, agricultural soil treatment, and in the production of glass and steel.
Geological facts
Limestone often contains well-preserved fossils of ancient marine organisms and is susceptible to dissolution by acidic water, creating fascinating cave systems and karst topography.
Field identification & locations
Easily identifiable in the field by its characteristic effervescence (fizzing) when a drop of weak hydrochloric acid or vinegar is applied to its surface. Commonly found in sedimentary basins worldwide.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary