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!
Cooper & Stanley (1990): "Identified on a specimen from an old working on the Deer Hills Quartz vein [NY31453626] where it is associated with carminite and scorodite (det. BM(NH): XRD, N. Thomson, pers. comm.)"