TRIPARTITE DIVISION OF THE SYSTEM 2REEPO4 - CaTh(PO4)2 - 2ThSiO4, DISCREDITATION OF BRABANTITE, AND RECOGNITION OF CHERALITE AS THE NAME FOR MEMBERS DOMINATED BY CaTh(PO4)2

The nomenclature for the system 2REEPO 4 – CaTh(PO 4 ) 2 – 2ThSiO 4 has been revised, to be consistent with CNMMN principles. Henceforth, only three names will be applied to members dominated by the respective end-member compositions monazite, cheralite, and huttonite. The name cheralite has priority over brabantite , which hereby is discredited. A six-fold diagram is replaced by a three-fold nomenclature diagram to conform to IMA rules. The parameters of cheralite are redefined. This proposal, IMA 2005/F, was approved by the CNMMN in April 2006.