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!
Brian Craik-Smith: "Article in the Russell Society newsletter (2000). All have been confirmed by XRD from my own specimens. There are also articles on the native copper, etc. from Dr. R.K. Harrison et al."
Quality for species:
Poor for species, only of interest for locality collectors. (#)