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): "As tiny pale green crystals on massive scorodite (M.P. Cooper Collection). Also reported from the 'Dumpy Stone' level (R.S.W. Braithwaite, pers. comm.)."