Discreditation of partzite

Abstract

The type specimen of partzite has been reinvestigated by powder X-ray diffraction and electron microprobe traverses. Re-examination of the type material shows that it is a mixture of several phases, intergrown on a submicrometre scale and hence not fully resolved by electron microprobe. Investigation of major-element spot analyses for correlations between elements indicates that the two dominant phases are a plumboromeite-like oxide phase and a chrysocolla-like amorphous Cu silicate. This analysis also suggested the presence of several minor phases that were too scarce to be detectable by X-ray diffraction, including acanthite, chlorargyrite, baryte, halite, and an Al-rich clay mineral. Lack of correlation between Si-corrected Cu content and Sb content implies that Cu is not a significant component of the romeite-group mineral. Partzite is therefore discredited as a valid mineral species. This proposal has been approved by the IMA CNMNC (proposal 16-B).