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!
pseudotetragonal twins of which {111} faces are sometimes replaced by {021} and show traces of the base {001}; elongated according to [001], almost always twinned, sometimes terminated by {111} and {021} (Cesàro, 1897)
Le Rocheux mine, Oneux, Theux, Liège, Wallonia, Belgium