[lahym-stohn] 
| a sedimentary rock consisting predominantly of calcium carbonate, varieties of which are formed from the skeletons of marine microorganisms and coral: used as a building stone and in the manufacture of lime. |
| lime·stone (līm'stōn') n. A common sedimentary rock consisting mostly of calcium carbonate, CaCO3, used as a building stone and in the manufacture of lime, carbon dioxide, and cement. |
Sedimentary rock formed primarily of calcium carbonate, often the skeletons of small marine organisms.
| limestone (līm'stōn') Pronunciation Key
A sedimentary rock consisting primarily of calcium carbonate, often in the form of the minerals calcite or aragonite, and sometimes with magnesium carbonate in the form of dolomite. Minor amounts of silica, feldspar, pyrite, and clay may also be present. Limestone can occur in many colors but is usually white, gray, or black. It forms either through the accumulation and compaction of fossil shells or other calcium-carbonate based marine organisms, such as coral, or through the chemical precipitation of calcium carbonate out of sea water. |
