THE MINERAL ROMANECHITE

• Chemical Formula: Ba(Mn+2, Mn+4)5O10-H2O , Hydrated Barium Manganese Oxide
• Class: Oxides and Hydroxides
• Uses: an ore of manganese and as a mineral specimen
• Specimens

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Romanechite is not a well known mineral, but is probably a part of most well rounded mineral collections. It is the primary constituent of psilomelane which is sometimes treated as a mineral and sometimes treated as a mixture of minerals or as a rock. Psilomelane is a mineral name that is losing its significance and romanechite is being used as the name for specimens previously known as psilomelane. However, this might be just as inaccurate since most specimens of psilomelane are not exclusively romanechite. Some mineral books consider romanechite and psilomelane to be synonyms for the same mineral. Here, romanechite is considered the pure form of Ba(Mn+2, Mn+4)5O10-H2O. It therefore differs from psilomelane in density and hardness, both of which are somewhat diminished in the mixture that is psilomelane.

Romanechite is an important ore of manganese. Manganese is a strategically valuable metal since it is an essential ingredient in steel and other alloys. The mining term "wad" is used to indicate ores that are a mixture of several manganese oxides such as psilomelane (romanechite), pyrolusite and others that are difficult to distinguish.

PHYSICAL CHARACTERISTICS:

• Color is variable from iron-black to bluish black to steel gray.
• Luster is submetallic to dull.
• Transparency crystals are opaque.
• Crystal System is monoclinic.
• Crystal Habits include massive, fibrous, botryoidal, columnar, stalactitic, concretionary, powdery and earthy.
• Cleavage is absent.
• Fracture is uneven.
• Hardness is 6.
• Specific Gravity is 4.7 - 5 (heavy for non-metallic minerals)
• Streak is brownish black.
• Associated Minerals are barite, hematite, quartz, pyrolusite and other manganese oxide minerals.
• Notable Occurances include Austinville, Wythe County., Virginia, Upper Pennisula of Michigan and Tuscon, Arizona, USA; Saxony, Germany; Saone et Loire, France; Cornwall, England; Ouro Preto, Minas Gerias, Brazil and elsewhere.
• Best Field Indicators are habits, luster, hardness, color and streak.