Nomenclature of the magnetoplumbite group

Abstract A nomenclature and classification scheme has been approved by IMA–CNMNC for the magnetoplumbite group, with the general formula A [ B 12 ]O 19 . The classification on the highest hierarchical level is decided by the dominant metal at the 12-coordinated A sites, at present leading to the magnetoplumbite ( A = Pb), hawthorneite ( A = Ba) and hibonite ( A = Ca) subgroups. Two species remain ungrouped. Most cations, with valences from 2+ to 5+, show a strong order over the five crystallographic B sites present in the crystal structure, which forms the basis for the definition of different mineral species. A new mineral name, chihuahuaite, is introduced and replaces hibonite-(Fe).