Calcite, limestone and marble | Earth Sciences
Back to Rocks and Minerals Articles Kelly Snyder and Peter Russell Calcite: A mineral consisting largely of calcium carbonate (CaCO3 ). Next to quartz, it is the most abundant of the Earth''s minerals. Crystallizing in the hexagonal system, calcite is noted for its wide variety of crystalline forms. Calcite is colourless or white when pure, but it may be of almost any colour