3.2" "Poker Chip" Calcite on Lustrous Sphalerite - Mitrovica, Kosovo

The Trepča Stari Trg mine, located in the Trepča complex, Trepča valley of the Mitrovica District, Kosovo, is the largest lead-zinc-silver mine in Europe and produces many fine mineral associations like this one. The mine's ore veins are hosted in Upper Triassic limestone that has been subjected to recrystallization. Minerals from this mine are quite stunning, formed via two stages of open-system and closed-system mineralization. The open-system stage formed a breccia that was injected with a high amount of outside mineral seepage. This process is responsible for most of the more attractive minerals to come out of the mine. These minerals include vivianite, pyrite, galena, sphalerite, hedenbergite, manganoan calcite, marcasite, arsenopyrite, and quartz.

Records of the mine's activity extend into the Middle Ages: it has been a large part of Kosovo's involvement in the mineral market to this day. The mine was temporarily shut down during the Kosovo war in the late 1980s, when equipment was destroyed and the mine was heavily flooded. Until the early 2000s the mine was inactive and the outflow of minerals ceased. Specimens from this mine are currently on the rarer side, though they should come back in full swing soon.