( 416 ) ORDER X.—ZINC. This Order contains the following species, Red Zinc- dre or Aed Oxide ot Zinc, Electric Calamine, Common Calamine, and Blende. I. Red Zinc-Ore, or Red Oxide of Zinc. Red Oxide of Zinc, Bruce. Red Zinc-ore, Bruce’s American Mineralogical Journal, p. Q6- External Characters. Its colours are blood-red and aurora red. It occurs massive, disseminated. Internally, on the fresh fracture it is shining; after •long exposure to the air it becomes dull, and even cover ed with a pearly crust. The principal fracture is foliated, the cross fracture eonehoidal. It is translucent on the edges, or opaque. It is easily scratched by the knife. It is brittle. It affords a streak which is brownish-yellow, approach ing to orange. Specific gravity, 6.220. Chemical Characters. It is soluble in the mineral acids. It is infusible with out addition before the blowpipe. With sub-borate of soda,