I bought this at Munich, having never heard of it before. According to MinDat, it is a "lead-rich variety of Boulangerite from Bayerland Mine, Pfaffenreuth, Waldsassen, Oberpfaelzer Wald, Upper Palatinate, Bavaria, Germany," which is indeed the location scribbled on the old label accompanying. Still, and interesting oddity, and for its shimmering surface not unattractive.