Carbonate Minerals

Minerals built around the carbonate ion, following the Nickel-Strunz carbonate class. Includes calcite, calcium carbonate, the most common carbonate mineral and the chief constituent of limestone and marble. Belongs here: any mineral whose defining anion group is carbonate. Does not belong here: the sedimentary or metamorphic rock a carbonate mineral forms in bulk, such as limestone or marble, which is a rock built largely from this mineral rather than the mineral itself, grouped under Sedimentary Rocks or Metamorphic Rocks. This class holds one live entity today; further carbonate minerals such as aragonite or magnesite have a real home waiting here as later mint waves add them, rather than a scheme invented to avoid a small class.