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!
Plate 44 from Wilson, Wendell. E.; Bartsch, Joel A.; Mauthner, Mark (2004) Masterpieces of the Mineral World. Houston Museum of Natural Science. [https://www.mindat.org/reference.php?id=18945017]
Quality for species:
Excellent - world class for species or very significant. (!!)
Significance:
Classic locality for this mineral (see references.)
Florence Mine, Egremont, Copeland, Cumbria, England, UK