Sulfate Minerals

Minerals built around the sulfate ion, following the Nickel-Strunz sulfate class. Includes gypsum, hydrated calcium sulfate, a common evaporite mineral. Belongs here: any mineral whose defining anion group is sulfate. Does not belong here: a sulfide mineral such as pyrite, where sulfur bonds directly to the metal with no oxygen present, or a halide mineral such as halite that commonly occurs in the same evaporite setting but bonds to a halogen rather than sulfate. This class holds one live entity today; further sulfate minerals such as barite or anhydrite have a real home waiting here as later mint waves add them.