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. Cooper & Stanley (1990): "Found in 1949 by Kingsbury and H. Neumann on the dumps from the 12, 30 and 60fm levels, and in situ in open-cast workings between Driggith and Sandbeds where it was more abundant. Associated minerals include malachite, cerussite, 'psilomelane', mimetite, linarite, and baryte (Kingsbury & Hartley, MS; Hartley, 1984)."
Driggith Mine, Caldbeck, Allerdale, Cumbria, England, UK