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!
Besides the ubiquitous massive material in all zones, large, distorted and rough pocket crystals, clear to smoky, sometimes gemmy, are known from the quartz-cleavelandite intermediate zone. These crystals are overgrowths on earlier fragmented quartz with "healed" faces and are commonly coated with albite, cookeite or fragments of matrix and included with white, acicular, hollow cavities of a former unknown mineral. Glassy micro-crystals associated with K-rich albite, cookeite, micas, bertrandite in secondary crystallizations.
Habit:
trigonal prisms
Colour:
colorless to pale grey, black, light brown, pink, yellow
Strickland Quarry, Strickland pegmatite, Collins Hill, Portland, Middlesex County, Connecticut, USA