psilomelane

psi·lom·e·lane

P0632000 (sī-lŏm′ə-lān′)n. A mixture of black manganese oxide minerals.

[Greek psīlos, bare + Greek melās, melan-, black.]

psilomelane

(sɪˈlɒmɪˌleɪn) n (Minerals) a common black to grey secondary mineral consisting of hydrated basic oxide of manganese and barium: a source of manganese. Formula: BaMn9O16(OH)4. Also called: romanicite [C19: from Greek psilos bare + melas black]

Thesaurus

Noun

psilomelane - a mineral consisting of hydrated basic oxide of manganese and barium; a source of manganeseatomic number 25, manganese, Mn - a hard brittle grey polyvalent metallic element that resembles iron but is not magnetic; used in making steel; occurs in many mineralsmineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition

Psilomelane

psilomelane

[‚sī·lō′me‚lān] (mineralogy) BaMn₉O₁₆(OH)₄ A massive, hard, black, botryoidal manganese oxide mineral mixture with a specific gravity ranging from 3.7 to 4.7.

Psilomelane

a mineral, a complex hydrous manganese oxide. Its approximate chemical composition is given by the formulas

BaMn²⁺Mn₉⁴⁺O₂₀.3H₂O

(Ba, Mn²⁺)₃(O, OH)₆Mn₈⁴⁺O₁₆

Psilomelane crystallizes in the monoclinic system. Its structure is formed by chains of the octahedral group MnO₆ with large channels, in which barium and molecules of water are positioned as in zeolite minerals. Ba ions in the channels can be replaced by ions of Ca, K, Pb, Zn, Co, Ni, Cu, U, and Sr; the Mn ions can be replaced by those of W, Fe, Al, and V. Psilomelane is opaque, and its color is black, steel gray, or brownish black. Its luster is submetallic; in fine-grained masses, it is dull. In massive form, the hardness on Mohs’ scale is 5–6; in finegrained masses, it is 1–3. The mineral’s density is 4,000–4,700 kg/m³.

Psilomelane occurs admixed with other oxides of manganese and iron in the form of smooth-surfaced, cryptocrystalline, or sinter aggregates. Soft, loosely aggregated substances that soil the fingers and possess a chemical composition similar to that of psilomelane are called wads. Psilomelane is of sedimentary or, less frequently, of hydrothermal origin. It also occurs in the zone of oxidation of oxide, silicate, and carbonate ores of manganese deposits. Psilomelane, together with other minerals that are oxides of manganese, is an important industrial ore in the smelting of ferromanganese. Psilomelane ores deficient in manganese are used for blending in the smelting of ordinary pig iron.

REFERENCE

Mineraly: Spravochnik, vol. 2, fasc. 3. Moscow, 1967.

psilomelane

psi·lom·e·lane

psilomelane

Psilomelane

psilomelane

Psilomelane

REFERENCE

psilomelane

Words related to psilomelane

noun a mineral consisting of hydrated basic oxide of manganese and barium

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