Mineralpedia Details for Semseyite
Named for Hungarian nobleman Andor von Semsey, who had an interest in minerals and could likely be credited as an amateur mineralogist. He is also honored in the naming of Andorite. Semseyite can be found in mid-temperature hydrothermal veins in localities including Romania, Germany, France, Scotland, Bolivia, Peru, the USA, Canada, and Japan as well as in small amounts at other occurrences.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/semseyite.pdf
Semseyite from Herja mine, Baia Mare, Maramures Co., Romania
Sheaf-like and stellate crystals to 5mm with a dull, metallic luster of Semseyite scattered on this complex matrix specimen loaded with a host of other minerals including black, fine crystals of Sphalerite and redish brown crystals of discoidal Siderite.