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New X-Ray Powder Data for Gorceixite, BaAl3(PO4)2(OH)5·H2O, an Evaluation of d-Spacings and Intensities, Pseudosymmetry and Its Influence on the Figure of Merit

Published online by Cambridge University Press:  10 January 2013

Frank N. Blanchard
Frank N. Blanchard
Affiliation:
Department of Geology, University of Florida, Gainesville, Florida 32611, U.S.A.
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Abstract

New powder and crystallographic data for gorceixite, a mineral of the crandallite subgroup of the alunite group, are reported and compared with current Powder Data File (PDF) patterns and with calculated patterns. Both d-spacings and intensities have been evaluated, and the results indicate a significant improvement over existing patterns. Indexing of the reflections is given for the true monoclinic symmetry, Cm (8), the pseudorhombohedral symmetry, (166) (to compare with structurally analogous minerals), and the pseudocubic symmetry, Fm3m (225). Because of the strong pseudosymmetry, the overall figure of merit is lower than would be the case for indexing in one of the pseudospace groups.

Type
Research Article
Information
Powder Diffraction , Volume 4 , Issue 4 , December 1989 , pp. 227 - 230
Copyright
Copyright © Cambridge University Press 1989

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