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MnO(OH) A brilliant steel-gray or black polymorphous mineral; crystallizes in the orthorhombic system. Also known as gray manganese ore.



a mineral of the oxide and hydroxide class. It has a chemical composition of MnO(OH) and contains 80.66 percent MnO; admixtures of Fe, Al, Ba, Pb, Cu, and other elements are sometimes present. Manganite crystallizes in the monoclinic system, forming prismatic steel-gray pseudoorthorhombic crystals with a submetallic luster and perfect cleavage. It generally occurs as black or brown (hydromanganite) finely crystalline masses. Concretions and oolitic formations are also widespread. Manganite is brittle. It has a hardness of 3-4 on Mohs’ scale and a density of 4,200-4,330 kg/m3.

Manganite, along with other manganese oxides (pyrolusite, psilomelane), enters into the composition of large sedimentary manganese ore deposits that are formed in the littoral zones of marine basins under conditions of some oxygen deficiency. Manganite also occurs in hydrothermal vein deposits in association with calcite, quartz, barite, and, sometimes, rhodochrosite. It is converted into sooty cryptocrystalline pyrolusite during surface oxidation. Manganite serves as an important source material in the manufacture of ferromanganese and other manganese alloys required for the smelting of special steels.


Mineraly; spravochnik, vol. 2, fasc. 3. Moscow, 1967.
References in periodicals archive ?
2), a large tabular body of fault breccia is composed of felsic rock cemented by manganese oxides and containing massive botryoidal psilomelane and braunite, as well as crystals and needles of manganite in rugs with barite.
Some of manganite nanocatalyst compounds with spinel structure were synthesized in the research through self-combusting sol-gel method, and their physicochemical properties were identified through various techniques.
The researchers used high-resolution scanning tunneling microscopy to generate images of the manganite surface -- down to the level of 30 picometers.
Shulyatev, Order and dynamics of intrinsic nanoscale inhomogeneities in manganites, Phys.
The longer papers consider radio-frequency electrodynamic properties of bulk lanthanum manganites, sinter-alloying and properties of manganese steels, surface treatment effects on bulk material fatigue resistance, developing controllable chemical synthetic routes to elemental selenium and some metal chalcogenides as bulk materials and thin films, and unusual properties of laser-processed strontium ruthenates.
In addition, The Telluride Summer Research Center, established in the mid-1980s, conducts high level science workshops in such areas as condensed phase dynamics, intramolecular dynamics, and certain manganites.
Typical multiferroics belong to the perovskite group of transition metal oxides, and include rare-earth manganites and ferrites.
Oxides like perovskites, ferrites, manganites (as SrTiO3, BaTiO3, Fe3O4, BiFeO3, CaMnO3) have becomethe building blocks for complex heterostructures coupling together at nanoscale different electronic and magnetic properties.