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A mixture of black manganese oxide minerals.

[Greek psīlos, bare + Greek melās, melan-, black.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(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]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.psilomelane - a mineral consisting of hydrated basic oxide of manganese and barium; a source of manganese
atomic 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 minerals
mineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Manganese is found as braunite, pyrolusite, psilomelane, and rhodochrosite.
Manganese oxides are mainly constituted by [Mn[O.sub.6]] octahedra with (1 x n) pyrolusite pore structure in ramsdellite family, barium and manganese ore (2 x n) pore structure in psilomelane family, barium, calcium, and manganese family (3 x n) pore structure, and (1 x [infinity]) layered structure manganese oxide minerals [12, 13].
More specifically, they suggested that since manganese does not occur free in nature, it must be present within teeth as a mineral such as pyrolusite (manganese dioxide) and psilomelane (an oxide mineral of manganese and barium), both of which are described as bluish-black with a metallic appearance.
Until 1828, mineralogists customarily used the term "prismatoidal manganese ore" for manganite (Mohs, 1825; Haidinger, 1826)--considering it among other black manganese species including "pyramidal manganese ore" (hausmannite), "brachytypous manganese ore" (braunite), "prismatic manganese ore" (pyrolusite) and "uncleavable manganese ore" ("psilomelane," now discredited in favor of cryptomelane).
Mineralogical composition of the fines at Balaghat and Ukwa mines is similar in nature and consists of Hollandite, Braunite, Psilomelane, Hematite, Apatite and Quartz.
2) at Jordan Mountain contains manganite intergrown with pyrolusite, and reduced amounts of hausmannite and psilomelane (Rose and Johnson 1990; Merlini 1998).