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romanechite

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Journal Article

Refinement of the substructure and superstructure of romanechite

Shirley Turner, Jeffrey E. Post
Published: 01 October 1988
American Mineralogist (1988) 73 (9-10): 1155–1161.
...Shirley Turner; Jeffrey E. Post Abstract The substructure and superstructure of romanechite, (Ba,H 2 O) 2 Mn 5 O 10 , were refined using a crystal from Schneeburg, Germany. The subcell is monoclinic, space group C 2/ m , with a = 13.929(1) Å, b = 2.8459(4) Å, c = 9.678(1) Å, β = 92.39(1)°, Z = 2...
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Raman spectra (633 nm) for <span class="search-highlight">romanechite</span> (France no. R2232) with crystals (el...

Raman spectra (633 nm) for romanechite (France no. R2232) with crystals (el...

Published: 01 August 2020
Figure 12. Raman spectra (633 nm) for romanechite (France no. R2232) 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
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Raman spectra (785 nm) for <span class="search-highlight">romanechite</span> specimens from three different local...

Raman spectra (785 nm) for romanechite specimens from three different local...

Published: 01 August 2020
Figure 13. Raman spectra (785 nm) for romanechite specimens from three different localities. Spectra for R2232 and C1818 were collected using a 100x objective from individual crystals, and for Van Horn from a massive specimen with crystals smaller than 0.5 µm.
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Raman spectra for <span class="search-highlight">romanechite</span> (Germany no. C1818) collected using four diff...

Raman spectra for romanechite (Germany no. C1818) collected using four diff...

Published: 01 August 2020
Figure 14. Raman spectra for romanechite (Germany no. C1818) collected using four different laser light wavelengths. (Color online.)
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Raman spectra for cryptomelane (532 nm; no. 89104), <span class="search-highlight">romanechite</span> (785 nm; R2...

Raman spectra for cryptomelane (532 nm; no. 89104), romanechite (785 nm; R2...

Published: 01 August 2020
Figure 20. Raman spectra for cryptomelane (532 nm; no. 89104), romanechite (785 nm; R2232), and todorokite (785 nm; no. 118176-13). (Todorokite rescaled × 4.5.) (Color online.)
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Backscattered scanning electron microscope (SEM) images of (A) <span class="search-highlight">romanèchite</span> ...

Backscattered scanning electron microscope (SEM) images of (A) romanèchite ...

Published: 11 May 2017
Figure 9. Backscattered scanning electron microscope (SEM) images of (A) romanèchite nodule sample JC-7B from the Shouns Prospect of the Mountain City window (as seen in Fig. 4H ); (B) enlarged image of A showing cracked, angular Ba-rich orthoclase (dark gray) encased in romanèchite (white
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Stacked normalized Mn K -edge XANES (left) and corresponding first-derivat...

Stacked normalized Mn K -edge XANES (left) and corresponding first-derivat...

Published: 01 May 2023
= cryptomelane; 6 = cryptomelane (syn); 7 = hollandite s.s.; 8 = pyrolusite; 9 = pyrolusite (syn); 10 = ramsdellite; 11 = romanèchite; 12 = romanèchite (Ba-free, syn); 13 = todorokite; 14 = todorokite (syn). (Color online.)
Journal Article

Thermal behavior of complex, tunnel-structure manganese oxides

David L. Bish, Jeffrey E. Post
Published: 01 February 1989
American Mineralogist (1989) 74 (1-2): 177–186.
...David L. Bish; Jeffrey E. Post Abstract The manganese oxide minerals coronadite, romanechite, and todorokite occur in a wide range of geologic settings and are common minor phases in massive deposits and as fracture linings. We have studied the thermal behavior of these minerals using a combination...
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Stacked k 3 -weighted Mn K -edge EXAFS spectra of phyllo- and tectomanga...

Stacked k 3 -weighted Mn K -edge EXAFS spectra of phyllo- and tectomanga...

Published: 01 May 2023
Figure 6. Stacked k 3 -weighted Mn K -edge EXAFS spectra of phyllo- and tectomanganates. 1 = acid Na-birnessite (hex, syn); 2 = δ-MnO 2 (syn); 3 = Na-birnessite (tricl, syn); 4 = lithiophorite; 5 = todorokite; 6 = todorokite (syn); 7 = romanèchite (nat); 8 = romanèchite (Ba-free, syn); 9
Journal Article

Isotopic dating of supergene manganese oxides from the Groote Eylandt Deposit, Northern Territory, Australia

D. Dammer, A. R. Chivas, I. McDougall
Journal: Economic Geology
Published: 01 April 1996
Economic Geology (1996) 91 (2): 386–401.
DOI: https://doi.org/10.2113/gsecongeo.91.2.386
... material balance equations, following determination of the contribution of radiogenic argon and potassium from the silicate residue. In this way, the times of formation of cryptomelane, Ba todorokite, and romanechite (and probably also vernadite) were estimated. In addition, high resolution 40 Ar/ 39 Ar...
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Raman spectroscopy study of manganese oxides: Tunnel structures

Jeffrey E. Post, David A. McKeown, Peter J. Heaney
Published: 01 August 2020
American Mineralogist (2020) 105 (8): 1175–1190.
DOI: https://doi.org/10.2138/am-2020-7390
...Figure 12. Raman spectra (633 nm) for romanechite (France no. R2232) 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...
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Geochemistry of supergene manganese oxide deposits, Groote Eylandt, Australia

Bernhard Pracejus, Barrie R. Bolton
Journal: Economic Geology
Published: 01 August 1992
Economic Geology (1992) 87 (5): 1310–1335.
DOI: https://doi.org/10.2113/gsecongeo.87.5.1310
... Aa), cryptomelane and todorokite ( approximately 0.7Aa), romanechite (no significant correlation detected), kaolinite ( approximately 0.6, 0.8, and 1.0 Aa), and goethite ( approximately 0.4 Aa). Generally, distinctive supergene horizons, enriched in certain elements (e.g., Zn, Sr) and minerals...
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The todorokite–buserite problem: further considerations

Roger G. Burns, Virginia Mee Burns, Harlan W. Stockman
Published: 01 February 1985
American Mineralogist (1985) 70 (1-2): 205–208.
...Roger G. Burns; Virginia Mee Burns; Harlan W. Stockman Abstract Todorokite has been shown in several recent HRTEM studies to have a tunnel structure analogous to that of romanechite (psilomelane). Further examinations of the structures and crystal chemistry of romanechite and todorokite suggest...
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Characterization of manganese oxide mineralogy in rock varnish and dendrites using X-ray absorption spectroscopy

David A. McKeown, Jeffrey E. Post
Published: 01 May 2001
American Mineralogist (2001) 86 (5-6): 701–713.
DOI: https://doi.org/10.2138/am-2001-5-611
... and romanechite, to layer phases, i.e., birnessite-family. Similar results were found for the dendrite samples, except that the variety of Mn-oxide phases is somewhat larger than those found for the varnishes. No correlations were found between Mn-oxide structure-type within these coatings and the corresponding...
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Representative X-ray diffraction patterns of Boléo Mn oxides with represent...

Representative X-ray diffraction patterns of Boléo Mn oxides with represent...

Published: 01 November 2011
Fig. 6 Representative X-ray diffraction patterns of Boléo Mn oxides with representative peak positions provided for cryptomelane, hollandite, pyrolusite, todorokite, and romanèchite.
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Raman modes determined using normal coordinate valence-force lattice dynami...

Raman modes determined using normal coordinate valence-force lattice dynami...

Published: 01 August 2020
Figure 11. Raman modes determined using normal coordinate valence-force lattice dynamics (LD) calculations for (left) hollandite (no. 127118) and (right) romanechite (France no. R2232) plotted as vertical lines below their respective Raman spectra (633 nm). (Color online.)
Journal Article

X-ray absorption spectroscopy study of Mn reference compounds for Mn speciation in terrestrial surface environments

Teresa Zahoransky, Anna V. Wegorzewski, Winnie Huong, Christian Mikutta
Published: 01 May 2023
American Mineralogist (2023) 108 (5): 847–864.
DOI: https://doi.org/10.2138/am-2022-8236
... = cryptomelane; 6 = cryptomelane (syn); 7 = hollandite s.s.; 8 = pyrolusite; 9 = pyrolusite (syn); 10 = ramsdellite; 11 = romanèchite; 12 = romanèchite (Ba-free, syn); 13 = todorokite; 14 = todorokite (syn). (Color online.) ...
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Tunnel structures: (a) woodruffite, 3 × 4; (b) Rb 0.27 MnO 2 (synthetic), ...

Tunnel structures: (a) woodruffite, 3 × 4; (b) Rb 0.27 MnO 2 (synthetic), ...

Published: 01 January 2005
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.
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Powder X-ray diffraction (XRD) patterns of nodule JC-7B showing (top) somew...

Powder X-ray diffraction (XRD) patterns of nodule JC-7B showing (top) somew...

Published: 11 May 2017
Figure 12. Powder X-ray diffraction (XRD) patterns of nodule JC-7B showing (top) somewhat sharp peaks of romanèchite mixed with quartz and Ba-rich orthoclase, while (bottom) nearby breccia matrix material in sample JC-7C shows hollandite-cryptomelane solid solutions. Both samples are from
Journal Article

A Short Outline of the Tunnel Oxides

Marco Pasero
Published: 01 January 2005
Reviews in Mineralogy and Geochemistry (2005) 57 (1): 291–305.
DOI: https://doi.org/10.2138/rmg.2005.57.9
...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. ...
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