Ullmannite, siderite Silberquelle mine, Obersdorf, ...
Description: Ullmannite, siderite Silberquelle mine, Obersdorf, Siegerland, Germany. 7 x 4,5 cm So-called "kallilite" (admixture with millerite and hauchecornite) from the type locality. With Bergakademie Freiberg label.