The loose jamesonite felted masses found in several vein-type Miocene ore deposits in Romania, at Herja in particular, host a very rich and peculiar mineral assemblage. This study concerns a novel morphological type of loose siderite crystals identified in this paragenesis. Additional to their macroscopic and microscopic investigation, powder X-ray diffraction (XRPD) analysis was carried out. Based on XRPD patterns, some pseudoxehagonal prisms, up to 10 mm in size, black to dark brown in color, with rugged surfaces and microscopic mosaic-like structures, were proved to be siderite. The described morphological type of siderite represents a novelty for Herja ore deposits, possibly also for Romania and for the entire Carpathian region.
Ghiurcă, Virgil and Pop, Dana
A novel morphological type of siderite in the jamesonite paragenesis from Herja (Maramures County, Romania),
Studia UBB Geologia
Available at: http://scholarcommons.usf.edu/geologia/vol51/iss1/art3