Perhaps the most rarely seen sulfide, in geodized brachiopods from Georgetown, is Sphalerite. Although approximately one third of geodized brachiopods will have Pyrite, Marcasite or Goethite, less than 1 in 100 will house Sphalerite. Sphalerite, at this locality, tends to form small dark reddish brown to black crystal groups and masses. This mineral will form…
