Limestone

n.

1.

A rock consisting chiefly of calcium carbonate or carbonate of lime. It sometimes contains also magnesium carbonate, and is then called magnesian or dolomitic limestone. Crystalline limestone is called marble.

Noun

1.

limestone - a sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals

atomic number 20, atomic number 6, C, Ca, calcite, calcium, carbon, rock, rottenstone, sedimentary rock, stone, tripoli