...Jeffrey E. Post; Peter J. Heaney; Christopher L. Cahill; Larry W. Finger Abstract The mineral woodruffite, Zn 2+ (Mn 4+ 1− x Mn 3+ x )O 2 · y H 2 O, x ~ 0.4 and y ~ 0.7, is the first known example of a new type of Mn oxide characterized by large tunnels that measure 3 and 4 octahedra (6.9 × 9.2 Å...

... with ω 2.055, ε 1.95 (Franklin). Color brownish black to iron-black. Woodruffite occurs at Sterling Hill, New Jersey, as botryoidal masses associated with chalcophanite and zincian cryptomelane in secondary zinc ores. Dense types have G = 3.71 and a hardness of 4½, with an iron-black color; also...

...Figure 18. Raman spectra (633 nm) for woodruffite (Mexico) with crystals (elongated along tunnels) oriented parallel (top) and perpendicular (bottom) to laser light polarization. Spectra labeled VV and VH were collected using parallel and crossed polarization conditions, respectively. (Color...

... , groutite, hollandite, lithiophorite, manganite, nsutite, quenselite, ramsdellite, romanechite, todorokite, and woodruffite are generally of supergene origin. In addition to established plots presently used to identify marine sedimentary exhalative deposits, the following diagnostic graphs were devised: Na...

..., hollandite, lithiophorite, manganite, manganese(III) manganate(IV), manganosite, manjiroite, marokite, nsutite, partridgeite, pyrolusite, quenselite, rancieite, ramsdellite, ro-manechite, sodium manganese(II,III) manganate(IV), todorokite, and woodruffite. The spectra indicate that well-ordered water occurs...

... to be persistently supergene: groutite, hydrohausmannite, lithiophorite, rancieite, hetaerolite, hydrohetaerolite, chalcophanite, crednerite, woodruffite, and wad. Another group of oxides appears to have been formed only by hypogene processes: manganosite, hausmannite, pyrochroite, bixbyite, galaxite, jacobsite...

...Figure 3. Tunnel structures: (a) woodruffite, 3 × 4; (b) Rb 0.27 MnO 2 (synthetic), 2 × 5; (c) RUB-7 (synthetic), 2 × 4; (d) todorokite, 3 × 3; (e) romanechite, 2 × 3; (f) hollandite, 2 × 2; (g) pyrolusite, 1 × 1. ...

...-crystal diffraction studies of romanechite and woodruffite that show Mn 3+ ordering into the octahedral sites at the edges of the triple and quadruple chains, respectively ( Turner and Post 1988 ; Post et al. 1999 ). As a pure MnO 2 framework is charge neutral, the lower valence octahedral cations...

... of minerals including hydrotalcite, manasseite, quintinite, and woodruffite; it is the only member of the group with a cation (Sr 2+ ) in the interlayer, which predominantly hosts carbonate. The mineral is named in memory of Russian mineralogist Pavel Karchevsky (1976–2002). The holotype has been split...

... realized by isolating Mn 3+ is greater than might be obtained by any strain reduction achieved by aligning Jahn-Teller distortions in rows. Additionally, XRD structure refinements reported for large tunnel structure Mn oxides, such as romanechite, todorokite, and woodruffite ( Turner and Post 1988 ; Post...

... oxides with different tunnel sizes, such as romanechite (3 × 2), todorokite (3 × 3), and woodruffite (3 × 4) ( Post 1999 ). The Mn L 3 ELNES can be mathematically represented by a sum of Gaussian functions, as shown in (Eq. 2): (2) \batchmode \documentclass[fleqn,10pt,legalpaper]{article...

..., todorokite, groutite, 10 Å buserite II, asbolane, and woodruffite) usually indicate marginal facies or ceasing of brine discharge for a long period ( Bischoff, 1969 ; Butuzova and Lisitsyna, 1984 ; Butuzova et al. , 1990 ). In the present work, a study of the Fe-Mn oxyhydroxides from the southern...