The mountain is built of Triassic Wetterstein limestone and Wetterstein dolomite. In the past, lead and zinc was mined on Peca, the shafts belonging to the Topla and Mežica mines. In addition to the ore, several rare minerals were discovered underground in the mountain, such as wulfenite and calcite. From the global standpoint, the Topla mine is it a rare proof of the sediment creation of lead-zinc ore deposits in supratidal zones. A mine on the mountain is accessible to mountain bikes.