Nomenclature of the Micas

Milan Rieder1, Giancarlo Cavazzini2, Yurii S. D' Yakonov3, Viktor A. Frank-Kamenetskii, Glauco Gottardi, Stephen Guggenheim4, Pavel W. Koval'5, Georg Müller6, Ana M. R. Neiva7, Edward W. Radoslovich§, Jean-Louis Robert8, Francesco P. Sassi2, Hiroshi Takeda9, Zdenĕk Weiss10 and David R. Wones
1 Department of Geochemistry, Mineralogy and Mineral Resources, Charles University, Albertov 6, 128 43 Praha 2, Czech Republic
2 Dipartimento di Mineralogia e Petrologia, Universitá di Padova, Corso Garibaldi, 37, I-35122 Padova, Italy
3 VSEGEI, Srednii pr., 74, 199 026 Sankt-Peterburg, Russia
4 Department of Geological Sciences, University of Illinois at Chicago, 845 West Taylor St., Chicago, Illinois 60607-7059, USA
5 Institut geokhimii SO AN Rossii, ul. Favorskogo 1 a, Irkutsk-33, Russia 664 033
6 Institut für Mineralogie und Mineralische Rohstoffe, Technische Universität Clausthal, Postfach 1253, D-38670 Clausthal-Zellerfeld, Germany
7 Departamento de Ciências da Terra, Universidade de Coimbra, Apartado 3014, 3049 Coimbra CODEX, Portugal
8 Centre de Recherche sur la Synthése et la Chimie des Minéraux, C.N.R.S., 1A, Rue de la Férollerie, 45071 Orléans CEDEX 2, France
9 Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino City, Chiba 275, Japan
10 Central Analytical Laboratory, Technical University of Mining and Metallurgy, Tř. 17.1istopadu, 708 33 Ostrava-Poruba, Czech Republic
Russia; died 1994.
Italy; died 1988.
§ Australia; resigned 1986.
U.S.A.; died 1984.

Abstract: End members and species defined with permissible ranges of composition are presented for the true micas, the brittle micas and the interlayer-cation-deficient micas. The determination of the crystallochemical formula for different available chemical data is outlined, and a system of modifiers and suffixes is given to allow the expression of unusual chemical substitutions or polytypic stacking arrangements. Tables of mica synonyms, varieties, ill-defined materials and a list of names formerly or erroneously used for micas are presented. The Mica Subcommittee was appointed by the Commission on New Minerals and Mineral Names (“Commission”) of the International Mineralogical Association (IMA). The definitions and recommendations presented were approved by the Commission.

Key Words: Mica • Nomenclature

Clays and Clay Minerals; October 1998 v. 46; no. 5; p. 586-595; DOI: 10.1346/CCMN.1998.0460513
© 1998, The Clay Minerals Society
Clay Minerals Society (www.clays.org)