Romanèchite ((Ba,H2O)2(Mn+4,Mn+3)5O10) is the primary constituent of psilomelane. Most psilomelane is not pure romanechite, so it is incorrect to consider them synonyms. Romanèchite is a valuable ore , which is used in steelmaking crystal structure of 6 and a specific gravity of 4.7-5. It is associated with hematite and other manganese oxide minerals. It has been found in France and various parts of the United States , including Arizona.