RECOMMENDED NOMENCLATURE FOR ZEOLITE MINERALS - REPORT OF THE SUBCOMMITTEE ON ZEOLITES OF THE INTERNATIONAL MINERALOGICAL ASSOCIATION, COMMISSION ON NEW MINERALS AND MINERAL NAMES

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission on New Miner als and Mineral Names. In a working definition of a zeolite mineral us ed for this review, structures containing an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and c omplete substitution by elements other than Si and Al is allowed. Sepa rate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abunda nt in atomic proportions. To name these, the appropriate chemical symb ol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite and wairakite in the phillipsite and an alcime series. Differences in space-group symmetry and in order-disord er relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solel y on Si:Al ratio except for heulandite (Si:Al < 4.0) and clinoptilolit e (Si:Al greater than or equal to 4.0). Dehydration, partial hydration and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term ''ideal formula'' should be avoided in referring to a simplified or averaged formula of zeolit e. Newly recognized species in compositional series are as follows: br ewsterite-Sr, -Ba; chabazite-Ca, -Na, -K; clinoptilolite-K, -Na, -Ca; dachiardite-Ca, -Na; erionite-Na, -K, -Ca; faujasite-Na, -Ca, -Mg; fer rierite-Mg, -K, -Na; gmelinite-Na, -Ca, -K; heulandite-Ca, -Na, -K, -S r; levyne-Ca, -Na; paulingite-K, -Ca; phillipsite-Na, -Ca, -K; stilbit e-Ca, -Na. Key references, type locality, origin of name, chemical dat a, IZA structure-type symbols, space-group symmetry, unit-cell dimensi ons, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. He rschelite, leonhardite, svetlozarite and wellsite are discredited as m ineral species names. Obsolete and discredited names are listed.