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!
Arsenopyrite in the Winthrop and Champion Lode quartz veins occurs as centimeter sized massive concentrations. Associated with pyrrhotite locally altered to pyrite. Native gold, generally as micron sized grains, is found, along with pyrite and chalcopyrite, in a network of thin fractures and veins cutting the arsenopyrite. The arsenopyrite is not the Co-Ni ore, earlier references to and analyses of "danaite" are probably from confusion with the loellingite ore veins.
Great Hill cobalt mines, Cobalt, East Hampton, Middlesex County, Connecticut, USA