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!
"Shepard [1837] initially identified the Co-Ni bearing arsenide as the cubic di-arsenide, smaltite but after obtaining and studying additional material from his own mine he pronounced it to be a new orthorhombic tri-arsenide for which he proposed the name "Chathamite"....In the mid 1850s Genth (in Goodrich, 1854) questioned Shepard's identification and suggested that Chathamite was simply an iron rich variety of the cubic arsenide chloanthite (a misconception that perpetuated up to, and including, the 7th edition of Dana's Manual of Mineralogy). As it turns out, Shepard's Chathamite is indeed orthorhombic, but today would be classified as a nickel-cobalt rich loellingite." Gray (2005)
