braunite


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braunite

(ˈbraʊnaɪt)
n
(Minerals) a brown or black mineral that consists of manganese oxide and silicate and is a source of manganese. Formula: 3Mn2O3.MnSiO3
[C19: named after A. E. Braun (1809–56), German official in the treasury at Gotha]
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Value (%, X-ray diffraction analysis w/w) Brittleness component (total) 72.95 Quartz 55.50 Feldspar 14.57 Cristobalite 2.88 Clay component (total) 5.85 Kaolinite 1.00 Illite 1.42 Smectite 3.43 Others (total) 20.97 Pyrite 4.08 Calcite 4.44 Muscovite 5.57 Annite 1.41 Marble 5.10 Braunite 0.37 Table 2: The soaking arrangement of shale samples.
Manganese is found as braunite, pyrolusite, psilomelane, and rhodochrosite.
The better specimens are undoubtedly those from the Cassagna mine, with pale green prismatic crystals up to 2 mm, sometimes associated with braunite, calcite, piemontite and barite crystals.
Fengjiashan Hubei amethyst, apophyllite, braunite, calcite, chalcopyrite, datolite, hubeite, ilvaite, inesite, japanese twins, pyrite, stilbite/stellarite, wollastonite Fenglin Jiangxi chalcocite Fengsandong Hubei amethyst, bornite, apophyllite, chalcopyrite, datolite, inesite, molybdenite, pyrite, parsettensite, stilbite Fushan Hebei vesuvianite, hematite Fushun Liaoning amber Fuyun Xinjiang, aquamarine, fluorite, garnet, hiddennite, Uygur A.R.
Associated minerals are: serandite-pectolite and braunite.
The type material came from a pocket in massive braunite and hausmannite and was associated with henritermierite, calcite, bultfonteinite and hematite.
Lately Charlie has been supervising specimen-prospecting in South Africa's famed Wessels manganese mine, with some impressive results which Rob Lavinsky of The Arkenstone had in his booth at Denver: a single flat (so far) of what are surely the finest specimens of the manganese silicate braunite ever found in the Wessels mine or, for that matter, anywhere.
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.
The presence of Mn-oxides such as braunite ([Mn.sub.2][O.sub.3]) and hausmanite ([Mn.sub.3][O.sub.4]) has been inferred by [H.sub.2][O.sub.2] decomposition in contact with Fe-Mn concretions.
Mineralogically, the manganese ores are mainly composed of braunite with subordinate amount of hematite in the fine-grained quartz matrix.
Adilabad (A.P) Pyrolusite, Psilimelane Braunite manganite, Quartz, Feldspar 2.
Manganese minerals predominate over iron (hematite) and include pyrolusite, psilomelane/cryptomelane, hausmanite, and braunite. The manganese mineralization occurs mainly as nodules within the sedimentary section, and both Mn and Fe minerals exhibit colloform textures.