cryptomelane

cryptomelane

[¦krip·tō·mə′lān]
(mineralogy)
KMn8O16·H2O A usually massive mineral, common in manganese ores; contains an oxide of manganese and potassium and crystallizes in the monoclinic system.
References in periodicals archive ?
Suib, "Influence of silver on the catalytic properties of the cryptomelane and Ag-hollandite types manganese oxides OMS-2 in the low-temperature CO oxidation," Applied Catalysis A: General, vol.
The manganese ore species of the veins are braunite, hausmannite, cryptomelane, "wad" and most commonly, and of greatest economic significance, pyrolusite and manganite.
Researchers from the Department of Energy's Pacific Northwest National Laboratory (PNNL) revealed earlier this month during the 230th national meeting of the American Chemical Society in Washington, DC, that the mineral cryptomelane "holds promise to absorb the toxic sulfur oxides that can degrade the emission control systems on diesel vehicles."
Then there was a single fiat of miniature-size specimens of the K-Mn oxide cryptomelane (yes, it's a valid species) collected in 2002 from a single pocket in pegmatite (!) near the town of Sao Geraldo do Baixio, Minas Gerais.
Many nodules were once hollow and have since been filled with manganese minerals (primarily psilomelane and cryptomelane), the probable coloring agents for the agate.
Romanechite (Ba,[H.sub.2]O)[.sub.2]([Mn.sup.4+],[Mn.sup.3+])[.sub.5][O.sub.10] and Cryptomelane K([Mn.sup.4+],[Mn.sup.3+])[.sub.8][O.sub.16]
Another, poorer, pattern is a fair match for cryptomelane, K[Mn.sub.8][O.sub.16]
Cryptomelane K([Mn.sup.+4],[[Mn.sup.+2]).sub.8][O.sub.16]
Relationship to other species: A member of the cryptomelane group, specifically the Ba-Fe dominant member.
The frondelite assemblage consists of residual heterosite, [TABULAR DATA FOR TABLE 1 OMITTED] montebrasite and triphylite enclosed by frondelite; massive replacement of frondelite by cyrilovite, cryptomelane and leucophosphite; and fracture coatings in frondelite of bermanite, cyrilovite, goethite, leucophosphite, lipscombite, mitridatite, moraesite, opal, phosphosiderite, rockbridgeite, variscite and manganese oxides.