Parajamesonite revisited: background of the discreditation of an enigmatic mineral species

Abstract

Original parajamesonite samples of Zsivny & Náray-Szabó (1947) and other authentic museum specimens containing the same material were studied by ore microscopy, electron probe microanalysis (EPMA) and X-ray powder diffraction (XRPD). The “parajamesonite crystals” proved to be pseudomorphs built of polycrystalline aggregates of euhedral jamesonite, sometimes intergrown with argentian tetrahedrite (freibergite) and/or ramdohrite. Other associated minerals are “plumosite”, i.e. fibrous jamesonite (rarely with boulangerite), iron-rich sphalerite, siderite, pyrrhotite, semseyite, a fizélyite-related mineral, and galena. All XRPD patterns correspond to jamesonite, without any similarity to the original pattern of parajamesonite. All these data prove that parajamesonite is actually jamesonite, permitting to discredit definitively parajamesonite as a mineral species.