Sulfate minerals are minerals bound with SO4. If the minerals are bound also with chrome, molybdenium or wolfram they create chromnites, molybdenites and wolframites. Those minerals are included in this group.
The creation of the sulfate minerals is bound to the volcanic and hydrothermal activity. They can also create under certain conditions in water (from water with large amounts of gyps in it to the crystals of gypsum) inland. Some minerals of this group are created after the degradation of a prime sulfate mineral.
From all minerals in this group, the chromnites are the most rare.