The chemical name for SO4 is sulfate. Almost all natural bodies of water contain sulfates, and these generally come from the presence of shales, sulfite ore oxidation or industrial waste. When rain dissolves, sulfate is a primary component.
The most common sulfate minerals include gypsum, barite and anhydrite. These form when SO4 groups combine with different metals. Sulfate-class minerals have the following characteristics: the density is average or above average, the hardness is average, a vitreous luster is present, and the minerals can be fluorescent and soluble. Initially, these minerals form in oxidation zones, evaporite deposits, veins and contact metamorphic zones.