This is the definition of a crystalline material. Naturally occurring amorphous materials are called mineraloids. Minerals are usually formed by inorganic processes . The traditional definition requires that minerals always be formed by inorganic processes. The tendency today is to include those materials that are formed by organic processes that otherwise fit the definition of a mineral.
Bacteria also play an important role in mineral formation.
Minerals are classified according to the fundamental ion or ionic group in the mineral. An ion is an atom that has lost or gained electrons. Because anions are formed by gaining electrons, or by forming complex ion groups, they are commonly the largest units in the crystal structure. Consequently, they will control the type of crystal that will develop during crystal growth. Crystals of minerals are usually regarded as structures of large fundamental anions with the smaller cations systematically fitting in between.