THE DIVERSITY AND OCCURRENCE OF POTASSIUM-DOMINANT AMPHIBOLES

Currently, the Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (IMA) recognizes seven amphibole species where potassium is the dominant A-site cation. These include potassic-ferrisadanagaite, potassic-fluororichterite, potassic-magnesiosadanagaite, potassicpargasite, potassicsadanagaite, potassic-chloropargasite and potassicleakeite. However, as a result of an evaluation of compositions of Cl-bearing amphibole samples from iron-oxide-rich ore systems and a comparison with data in the reviewed literature, fourteen additional naturally occurring potassium-dominant amphiboles can be justified from selected published chemical data using recommended protocols for normalization. In keeping with accepted amphibole nomenclature, these new amphibole end-members would be “potassichastingsite”, “potassic-chlorohastingsite”, “potassic-ferropargasite”, “potassic-chloro-ferropargasite”, “potassic-aluminosadanagaite”, “potassic-chlorosadanagaite”, “potassic-chloro-ferro-edenite”, “potassicrichterite”, “potassic-ferrorichterite”, “potassic-fluoro