Vote for your favorite mineral in #MinCup26! - Sphalerite vs. Anorthite Both zinc ore Sphalerite and calcium plagioclase feldspar Anorthite have perfect cleavage that will split cleanly if you hit them with a hammer, but only one can claim a larger split of your votes!
Bridges et al. (2008): "Cooper and Stanley (1990) note that chalcocite and digenite have been reported from Red Gill Mine, but early identifications of chalcocite have to be regarded with suspicion, since only relatively recently has it become possible to distinguish the grey copper sulphides from each other and even then only with some difficulty."
