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!
'Serpentine Subgroup' (not an IMA approved species)
Formula:
D3[Si2O5](OH)4
Comments:
Type locality for variety "Williamsite", a gemmy bright green serpentine often used as a semi-precious stone. Often associated with Chromite at this locality. discovered in 1849 by Lewis W. Williams, whom also first described Zaratite (Emerald Nickel) at Wood's Chrome Mine the same year.
Wood's Chrome Mine, Texas, Little Britain Township, Lancaster County, Pennsylvania, USA