This sphalerite is from the Madan Ore Field in the Rhodope Mountains, Smolyan Oblast, Bulgaria. This area contains several ore bodies that have been mined for hundreds of years. Dozens of mines were worked for the recovery of lead and zinc. It contains 75 different mineral species including sphalerite. It is a sulfide containing the elements Zn and S. This specimen is a rosette type formation with intact and terminated crystals on all sides. The crystals are interpenetrating and have coin like tetragonal crystals with minor calcites. The piece displays well from all sides. It measures 2 x 1 1/2 x 1 1/2 inches or 50 x 38 x 38 mm.