Minerals are classified according to their chemical properties. Except for the native element class, the chemical basis for classifying minerals is the anion, the negatively charged ion that usually shows up at the end of the chemical formula of the mineral. For example, the sulfides are based on the sufur ion, S2–. Pyrite, for example, FeS2, is a sulfide mineral. In some cases, the anion is of a mineral class is polyatomic, such as (CO3)2–, the carbonate ion. The major classes of minerals are:
silicates
sulfides
carbonates
oxides
halides
sulfates
phosphates
native elements
