Calcite vs. Limestone — What's the Difference?

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 3 as "calcite".

Limestone is a common type of carbonate sedimentary rock. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3).

A common crystalline form of natural calcium carbonate, CaCO3, that is the basic constituent of limestone, marble, and chalk. Also called calcspar.

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.

(mineral) a very widely distributed crystalline form of calcium carbonate, CaCO₃, found as limestone, chalk and marble

An abundant rock of marine and fresh-water sediments; primarily composed of calcite (CaCO₃); it occurs in a variety of forms, both crystalline and amorphous.

Calcium carbonate, or carbonate of lime. It is rhombohedral in its crystallization, and thus distinguished from aragonite. It includes common limestone, chalk, and marble. Called also calc-spar and calcareous spar.

Pertaining to or made of limestone.

A common mineral consisting of crystallized calcium carbonate; a major constituent of limestone

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.

A sedimentary rock consisting mainly of calcium that was deposited by the remains of marine animals