Galena, PbS, and Quartz, SiO2. Aberdaunant mine, Nr. Llanidloes, Central Wales Orefield. Collected from spoil heaps at the mine, these specimens are a galena- quartz breccia The quartz is massive with no sign of crystals. The galena is also massive with just a small indication of a few small broken crystals, which display the natural cleavage planes. As is often the case in this area, some of the exposed broken surfaces have a bright blue sheen.