Description
The mineral psilomelane is a hydrated barium-manganese oxide with the chemical formula Ba·(H2O)Mn3+5O10. The opaque iron-black or dark gray psilomelane has a submetallic luster, a brownish-black streak color, and the mineral does not exhibit cleavage. The crystal system is monoclinic. Psilomelane has an average density of 4.55, a hardness of 5 to 6, and is not radioactive. The name of the mineral psilomelane is derived from the Greek words psilos ("smooth") and melas, meaning "black." Psilomelane is a common mineral in manganese ores. Today, it is no longer officially recognized by the IMA and is called the mineral romanechite. Psilomelane is found, among other places, in Compton, Virginia.
