gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1947.028.198.05 Subcalcic Ferroaugite from Mount Arthur, East Griqualand Poldervaart Arie M.Sc., Ph.D. Geology Department, University of Cape Town.

Communicated by Prof. F. Walker

 9 1947 28 198 159 163 Copyright © 1947, The Mineralogical Society 1947 Abstract

A new analysis of a subcalcic ferroaugite is given. The calculated composition is compared with compositions deduced from the optical properties according to various methods. Slight modifications to Benson's nomenclature of the clinopyroxenes are suggested.