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!
Cooper & Stanley (1990): "In small amounts from the 'lowest level at 1500ft [450m]' (Hartley, 1984); also as crusts of minute crystals on altered sulphides from the 'Golden Hugh' where it appears to still be forming on the mine walls."
Silver Gill, Roughton Gill, Caldbeck, Allerdale, Cumbria, England, UK