... industries,best price and prompt delivery are guranteed. FELDSPAR comprises a group of minerals containing potassium, sodium ... rock-forming minerals. The common feldspar is potassium feldspar, namely, orthoclase (K2O, Al2O3, 6SiO2). Sodium feldspar is albite (Na2O, Al2O3 ... veins consisting mainly of feldspar, quartz-feldspar veins and also occur with mica pegmatites. Feldspar is of widespread occurrence ...