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!
This bluish tourmaline was assigned to uvite by chem. analysis and lattice parameters in Ertl, A. (1995): Elbait, Olenit, Dravit-Buergerit-Mischkristalle, Dravit, Uvit und ein neuer Al-Turmalin (?) von österreichischen Fundstellen. - Mitt. Österr. Miner. Ges., 140, 55-72.