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): "Described as 'crystallized and acicular' by Greg & Lettsom (1858: 391). A mining report of 1865 (Shaw archive, Carlisle, D/Sh/1/9) describes the 60fm level 'driven 15fm [27m] all in ore worth up to [2 tons] per fm all carbonate'."