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 Mine rals and Mineral Names. In a working definition of a zeolite mineral u sed for this review, structures containing an interrupted framework of tetrahedra are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Sep arate species are recognized in topologically distinctive compositiona l series in which different extra-framework cations are the most abund ant in atomic proportions. To name these, the appropriate chemical sym bol is attached by a hyphen to the series name as a suffix, except for the names harmotome, pollucite and wairakite in the phillipsite and a nalcime series. Differences in space-group symmetry and in order-disor der relationships in zeolites having the same topologically distinctiv e framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished sole ly on the ratio Si : Al except for heulandite (Si :Al < 4.0) and clino ptilolite (Si :Al greater than or equal to 4.0). Dehydration, partial hydration, and overhydration are not sufficient grounds for the recogn ition of separate species of zeolites. Use of the term ''ideal formula '' should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba, chabazire-Ca, -Na, -K, clinoptilolite-K, -Na, -Ca, dachiardite-Ca, -Na, erionite-Na, -K, -Ca, faujasite-Na, -C a, -Mg, fenierite-Mg, -K, -Na, gmelinite-Na, -Ca, -K, heulandite-Ca, - Na, -K, -Sr, levyne-Ca, -Na, paulingite-K, -Ca, phillipsite-Na, -Ca, - K, and stilbite-Ca, -Na. Key references, type locality, origin of name , chemical data, IZA structure-type symbols, space-group symmetry, uni t-cell dimensions, and comments on structure are listed for 13 composi tional series, 82 accepted zeolite mineral species, and three of doubt ful status. Herschelite, leonhardite, svetlozarite, and wellsite are d iscredited as mineral species names. Obsolete and discredited names ar e listed.