How to name amphiboles after the IMA2012 report: rules of thumb and a new PC program for monoclinic amphiboles

Abstract

 Major changes have been introduced by the new scheme for amphibole classification and nomenclature for the amphibole supergroup recently approved by the Commission on New Minerals Nomenclature and Classification of the International Mineralogical Association, a scheme which adheres to the concepts of dominant group valency and dominant ion. The hierarchy of classification now proceeds through the W (→groups), B (→subgroups), and C and A (→rootnames) ions in a rational and comprehensive scheme which takes into account aspects of amphibole stability based on synthesis work. The new rules are here discussed in a simple and application-oriented manner, and the procedure to be followed to correctly classify and name amphibole compositions is outlined. A PC program (written in VisualBasic) for naming monoclinic amphiboles according to the new rules is now available by downloading from the website of CNR-IGG, UOS of Pavia:  http://www_crystal.unipv.it/labcris/AMPH2012.zip