Romanèchite

Romanèchite
Romanèchite, from the Marquette County, Michigan, US.
General
Category	Oxide minerals
Formula (repeating unit)	(Ba,H2O)2(Mn+4,Mn+3)5O10
Strunz classification	4.DK.10
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/m
Identification
Mohs scale hardness	6-6.5
Luster	Submetallic
Streak	Blue-black
References

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