White Dolomite in rhombs and casts with colorless Adularia, Pyrite and Quartz. This is a good typical specimen from Homestake's "water course" mineralization, which occured deep underground as extremely hot water conduits. Often times, these dikes were filled with spectacular crystals of quartz, adularia, pyrite, sphalerite etc. I often thought these deposits were actually alpine type mineralization, just underground however but still in mountainous terrain.