New Data on Georgiadesite

Roland C. Rouse and Pete J. Dunn
Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560, USA

Abstract: The chemistry and crystallography of type georgiadesite from Laurion, Greece, have been reexamined using electron microprobe analysis along with powder and single-crystal X-ray diffraction. Georgiadesite is monoclinic, P21/c, with a = 13.803(10), b = 7.910(2), c = 10.812(4) Å, and β = 102.68(3)°. No twinning was observed. The probable chemical formula is either Pb16(AsO4)4Cl14O2(OH)2 or Pb16(AsO4)4Cl14(OH)6. The calculated densities for these formulae are 6.39 and 6.44 g/cm3, respectively, compared to a measured value of 6.3 + 0.3 g/cm3.

Mineralogical Magazine; June 1983 v. 47; no. 343; p. 219-220; DOI: 10.1180/minmag.1983.047.343.12
© 1983, The Mineralogical Society
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