Sphalerite ball on Quartz matrix from Borieva Mine, Madan Municipality, Smolyan Province, Bulgaria. A remarkable sphalerite ball perched elegantly on a sparkling quartz matrix, originating from the well-known Borieva Mine, Madan Municipality, Smolyan Province, Bulgaria. The lustrous, dark sphalerite forms a distinct spherical aggregate set atop a bed of sharply terminated quartz crystals, creating a beautiful contrast in both form and texture. The Borieva Mine in Madan Municipality, Smolyan Province, Bulgaria, is part of the famous Madan ore field known for its lead and zinc deposits. Mining in this region dates back to ancient times, with the Borieva Mine including several ore bodies like Petrovitsa and Yuzhna Petrovitsa. The mine has yielded notable mineral specimens, especially galena, sphalerite, pyrite, and quartz, making it well-regarded among mineral collectors. Historically, Madan and its mines contributed significantly to the local economy and remain key sources for world-class sulfide minerals.