Roggianite: Revised Chemical Formula and Zeolitic Properties

E. Passaglia and Giovanna Vezzalini
Istituto di Mineralogia, Universita' di Ferrara, Corso Ercole I d'Este 32, 44100 Ferrara, Italy
Istituto di Mineralogia e Petrologia, Universita' di Modena, via S. Eufemia 19, 41100 Modena, Italy

Abstract: The holotype roggianite from Alpe Rosso (Novara, Italy) has been chemically re-analysed using modern analytical procedures (microprobe, atomic absorption spectrophotometer, TG analyses) and tested for its zeolitic behaviour. When compared with that given in the original description, the new chemical composition shows an appreciable amount of Be and a different Si/Al ratio. On the basis of its structural data, the chemical formula here proposed for roggianite is: (Ca14.24Sr0.01Na0.37K0.56)Σ15.18[(Be5.29Al14.92Si27.79)Σ48O89.96(OH)14](OH)2·33.68H2O An accurate powder pattern, index taking into account the structural factors, is also given. Since the mineral showed an almost complete rehydration after heating to 750°C and an appreciable ion exchange capacity, it must be considered as belonging to the zeolitic group of minerals, and, in this frame, it represents the first and up to now the only zeolite with Be as fundamental constituent and, like partheite, with OH groups in the framework.

Keywords: roggianite • zeolitic properties • Alpe Rosso • Italy

Mineralogical Magazine; April 1988 v. 52; no. 365; p. 201-206; DOI: 10.1180/minmag.1988.052.365.06
© 1988, The Mineralogical Society
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