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!
"In the [Marcelle and Charles] Weber collection, the author saw a specimen of oxidized metallic minerals, from the Thomaston Dam railroad cut, containing tiny brown prisms of what may be the endlichite variety of this mineral. This remains in the problematical category." Schooner (1961)
Quality for species:
Poor for species, only of interest for locality collectors. (#)