Limestone is a type of sedimentary rock primarily composed of calcium carbonate (CaCO3), usually in the form of the minerals calcite and aragonite
. It often forms from the accumulation and compaction of marine organism shells, coral, and other fossilized debris, making it rich in fossils
. Limestone can also form through chemical precipitation of calcium carbonate from water
. Key characteristics of limestone include:
- Composition: Mostly calcium carbonate, sometimes with magnesium (dolomite) or iron (siderite) impurities
- Texture: Typically fine-grained but can vary from smooth to rough, often containing visible fossil fragments or shell pieces
- Color: Usually white to gray, but can vary due to impurities such as clay, sand, or organic material
- Formation environment: Mostly formed in shallow marine environments like continental shelves
In summary, limestone is a sedimentary rock made predominantly of calcium carbonate, formed biologically or chemically, and commonly contains fossils
