The Trepca Pb-Zn-Ag skarn deposit in Kosovo is spatially and temporarily related to the phreatomagmatic breccia of Oligocene age (~23Ma). The deposit shows features typical for skarn deposits worldwide, including a stage of isochemical metamorphism, a prograde stage of an anhydrous, low oxygen and low sulfur fugacity character, and a retrograde stage characterized by an increase in the water activity as well as by an increase in oxygen and sulfur fugacities. The mineralization is hosted by the recrystallized Upper Triassic limestone. The prograde mineralization consists mainly of Ca-Fe-Mn + or - Mg pyroxenes. The phreatomagmatic breccia was developed along a NW dipping contact between the ore bearing recrystallized limestone and the overlying schist. It has an inverted cone shape with vertical extension up to 800 m and a diameter of up to 150 m. The upper part of the diatreme is characterized by the presence of a hydrothermally altered rootless quartz-latite dyke surrounded by an unsorted polymict breccia mantle. Despite the alteration processes, the dyke has a preserved porphyritic texture.