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Natural zeolites: odd genesis, intrinsic beauty,
wide applicationsZelimir Gabelica
LPI-GSEC, ENSCMu, Mulhouse, France
2nd FEZA School, Paris, September 1-2, 2008Mr Toni WIELAND
Mr Eddy VANDERMEERSCHE
Dr Roger WARIN
Dr Sabine VALANGE
Dr Ermanno GALLI
Acknowledgments:
ZEOLITE GROUP
Reference: Fleischer’s Glossary of Mineral SpeciesM.E. Back & J.A. Mandarino, Miner. Rec. Ed., Tuscon (AZ), 2008, 345 pp
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MINERAL GROUPSMINERAL GROUPSA mineral group, consisting of at least 3 species, involves
members having similar chemical formulae and, ideally, the same general structure, thus belonging to the same crystal
system (not often respected)
ZEOLITE GROUPSZEOLITE GROUPS(Alumino)silicates (“and related”?) with framework structures
containing open cavities in the form of channels and cages, usually occupied by
H2O and extra-framework (charge-compensating) cations. Crystallography varies within the group.
90 officially recognized species (as for August 2008, including Direnzoite) are partitioned between series species and non-series species
SERIES
Series can be defined on the basis of dominant extra-framework cations
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In the case of zeolites, series were established for 15 generic species15 generic species, each involving 2 or more species:
BRE (Monoclinic): Ba, Sr Ex: Brewsterite-Ba
CHA (Trigonal): Na, K, Ca, Sr Note: Herschellite (discredited)
Chabasite-KCLI (Monoclinic): Na, K, Ca
DAC (Monoclinic): Na, Ca
ERI (Hexagonal): Na, K, Ca
FAU (Cubic): Na, Ca, Mg Note: Kaiserstuhl: presence of both FAU-Na & FAU-
- Analcime: 5 different crystal systems: Cub., Tet., Orth., Mon., Tric.- Leucite (and Ammonioleucite) do belong to the zeolite group, but not their analog Sodalite (see later “Sodalite Subgroup” of CAN-SOD Group)- Barrerite (Orthorhombic) is different from Stilbite-Na (Monoclinic)
- Sodalite sub-group:Cubic or tetragonal species involving cuboctahedral “sodalite cages”Filled with clusters of atoms (cations, SO4, Cl, (poly)sulphides…)11 speciesEx: Sodalite (Cl), Lazurite (S, Cl, OH), Haüyne (SO4),
Genthelvite (Fe & S), Helvine (Mn & S) …
CANCRINITE-SODALITE GROUP
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- Sodalite sub-group: (continued)
NB: Tsaregorodsevite (TMA)4[Si2(Si0.5Al0.5)O6]2, involves TMA+ cations that (probably) act as both structure-directing agents (SOD cages) and counterions to one framework negative charge.