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!
Common as cleavable masses in the hydrothermal fault veins with fluorite, quartz, calcite, sphalerite, zeolites, etc. Crystals in open spaces typically range in size to about 5 cm, but a 7 kg galena crystal (10 cm on a side) was reportedly found by a workman at the site. Some <0.5 cm octahedra were also found.
Thomaston Dam railroad cut, Thomaston Dam, Thomaston, Litchfield County, Connecticut, USA