Phurcalite from Dartmoor, Southwest England, and Its Identity with ‘Nisaite’ from Portugal

R. S. W. Braithwalte, W. H. Paar and J. E. Chisholm
Chemistry Department, University of Manchester Institute of Science and Technology, Manchester M60 1QD
Institut für Geowissenschaften, Mineralogie-Petrographie, der Universität Salzburg, Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria
Department of Mineralogy, British Museum (Natural History), Cromwell Road, London, SW7 5BD

Abstract: Yellow blades on joint surfaces in granite from Merrivale quarry, Dartmoor, Devon, are shown to be of a slightly aresenatian variety of phurcalite by X-ray powder diffraction, infrared spectroscopy, electron microprobe and thermal analyses and optical methods. The results from these techniques are tabulated, including assignments for infrared absorption bands. Comparison of X-ray powder diffraction, infrared spectroscopic and optical data with those obtained from samples of ‘nisaite’, an incompletely described mineral from Nisa, Portugal, indicates that the latter is also phurcalite.

Keywords: phurcalite • nisaite • Dartmoor • Portugal

Mineralogical Magazine; December 1989 v. 53; no. 373; p. 583-589; DOI: 10.1180/minmag.1989.053.373.09
© 1989, The Mineralogical Society
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