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!
Kingsbury reference. Kingsbury (1957): "From the outcrop of the main Driggith-Sandbed vein near Caldbeck, in an old opencast between the two mines: here colourless phosgenite has been found with anglesite in somewhat decomposed, massive granular galena."