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Article: Afghanite from Mount Vesuvius: a rediscovery.
- Article from:
- The Mineralogical Record
- Article date:
- March 1, 1996
- Author:
CopyrightCOPYRIGHT 1996 The Mineralogical, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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INTRODUCTION
Afghanite [[(Na,Ca,K).sub.8][(Si,Al).sub.12][O.sub.24][(S[O.sub.4],Cl,C[O.s ub.3],[H.sub.2]O).sub.3]] is a feldspathoid of the cancrinite group. Minerals of this group (see Table 1) are hexagonal silicates having the general formula [A.sub.6-8][(Si,Al).sub.12][O.sub.24] [[(S[O.sub.4]),(C[O.sub.3]),Cl, (OH),[H.sub.2]O].sub.2-4], where A = Na, Ca and/or K.
Afghanite was officially described as a new species by Bariand et al. (1968) based on specimens from the Sar-e-Sang lazurite deposit in Afghanistan. It has since been reported from ten localities worldwide (see Table 2), half of them being volcanic occurrences in Italy. Typical associated minerals ...