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!
"Here and there small microscopic wulfenites occur both as pseudocubic (similar to the Loudville, Massachusetts, material only considerably smaller) as well as bipyramidal crystals (Marcelle Weber, personal communication, 1984)." (Segeler & Molon, 1985). At least one former Ron Januzzi specimen of a platy orange mineral in crude micro-crystals turned out to be calcite.