The discreditation of oboyerite and a note on the crystal structure of plumbotellurite

摘要

The mineral 'oboyerite', first described in 1979 from the Grand Central mine, Tombstone, Cochise County, Arizona, USA, has been re-examined. The type specimen from the Natural History Museum, London and a specimen from the Natural History Museum of Los Angeles County (traceable to S. A Williams, who first described 'oboyerite') were analysed in this study. The discreditation of 'oboyerite' as a valid mineral species has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (Proposal 19-D). Single-crystal X-ray diffraction, powder X-ray diffraction, electron probe microanalysis and scanning electron microscopy were all employed to show that `oboyerite' is formed of at least two distinct phases, including the lead-tellurium oxysalt minerals ottoite and plumbotellurite. During the course of the discreditation, plumbotellurite was confirmed to be identical to the synthetic compound alpha-Pb2+Te4+O3. Previously, in some mineralogical literature plumbotellurite was described as orthorhombic with no known crystal structure.