Serpentinization is a hydration and metamorphic transformation of ferromagnesian minerals, such as olivine and pyroxene, in mafic and ultramafic rock. Minerals formed by serpentinization include the serpentine group minerals (antigorite, lizardite, chrysotile), brucite, talc, Ni-Fe alloys, and magnetite. The mineral alteration is particularly important at the sea floor at tectonic plate boundaries.