Specimens of sphalerite with calcite from Trepca Mine, Stan Terg, Mitrovica in Kosovo. Sphalerite is a zinc sulfide mineral and the primary ore of zinc. These samples have a high content of iron giving them a striking submetallic lustre and and opaque, dark grey appearance. Calcite is one of the index minerals in the Moh's scale at number 3, as it is a fairly soft mineral, able to be scratched by your finger nail. These beautiful pieces come from Trepca mine in Stan Terg, Mitovica, Kosovo, a region which has only recently become safely accessible and are supplied with both a white card tray and information label. The specimens show a wonderful contrast between the dark metallic grey of the sphalerite and the white crystalline calcite and would make an excellent addition to any mineral collection.