On the definition of distinct mineral species: A critique of current IMA-CNMNC procedures

Abstract The criteria for the definition of a new mineral species currently used by Commission on New Minerals Nomenclature and Classification (CNMNC) International Mineralogical Association are critically examined. In particular, rule dominant constituent can violate laws conservation electric charge. A series additional rules: (1) valency-imposed double site-occupancy; (2) dominant-valency rule; (3) site-total-charge approach, have been developed in an attempt to correct this error. However, none these rules overcome fundamental flaw introduced constituent, chemical formulae resulting from application requirements end-member, particularly that electroneutrality. As result, IMA–CNMNC cannot derive end-member some groups minerals, giving rise many ad hoc decisions defining distinct species.