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tuhualite

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Journal Article
Published: 01 March 2018
European Journal of Mineralogy (2018) 30 (2): 367–373.
...Bogusław Bagiński; Ray Macdonald; John C. White; Lidia Jeżak An occurrence of the rare mineral tuhualite (NaFe 3+ Fe 2+ Si 6 O 15 ) is reported in a peralkaline rhyolitic ignimbrite from the island of Pantelleria, Italy. The mineral formed during devitrification of glassy fiamme and varies in form...
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Journal Article
Published: 01 September 2001
American Mineralogist (2001) 86 (9): 973–980.
...Michael N. Taran; George R. Rossman Abstract Polarized optical absorption spectra of a rare Fe 2+ , Fe 3+ -bearing silicate mineral, tuhualite, (Na,K) 2 Fe 2 2+ Fe 2 3+ Si 12 O 30 , were measured at room temperature in the range 350–4000 nm (ca. 28500–2500 cm −1 ). The spectra display a number...
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Journal Article
Published: 01 June 1977
American Mineralogist (1977) 62 (5-6): 416–420.
..., and density of 2.79 g/cm 3 . Optically, zektzerite is biaxial negative, almost isotropic, with 2 V x = ∼0°. Indices are α = 1.582(3), β = 1.584(3), and γ = 1.584(3) with orientation X = a , Y = b , and Z = c . Dispersion is very weak, r > υ. Zektzerite is closely related to tuhualite, ( N a , K ) 2 F e 2 2...
Image
(A) BSE image, showing <span class="search-highlight">tuhualite</span> (Tuh) crystals in both fiamme and pre-weld...
Published: 01 March 2018
Fig. 2 (A) BSE image, showing tuhualite (Tuh) crystals in both fiamme and pre-welding vesicles in a type one layer. Crystals representing the range of forms have been arrowed. (B) BSE image of tuhualite, sodic amphibole (Am) and aegirine (cpx) projecting from the wall into an empty vesicle. (C
Image
(A) BSE image, showing <span class="search-highlight">tuhualite</span> (Tuh) crystals in both fiamme and pre-weld...
Published: 01 March 2018
Fig. 2 (A) BSE image, showing tuhualite (Tuh) crystals in both fiamme and pre-welding vesicles in a type one layer. Crystals representing the range of forms have been arrowed. (B) BSE image of tuhualite, sodic amphibole (Am) and aegirine (cpx) projecting from the wall into an empty vesicle. (C
Image
(A) Photograph of a polished slab of the <span class="search-highlight">tuhualite</span>-bearing ignimbrite. Note...
Published: 01 March 2018
Fig. 1 (A) Photograph of a polished slab of the tuhualite-bearing ignimbrite. Note the layered structure, with layers (numbered) varying in degree of vesicularity and size of alkali feldspar phenocrysts (Kfs). Tuhualite is found only in layer type 1. The yellow phase is possibly an Fe ± Mn
Image
The structure of  <span class="search-highlight">tuhualite</span>  projected ( a ) onto (100) and ( b ) along the...
Published: 26 February 2020
Fig. 47. The structure of tuhualite projected ( a ) onto (100) and ( b ) along the c -axis. Fine dashed black lines outline the unit cell and H atoms associated with (H 2 O) groups have been omitted for clarity.
Image
Plots of Mn (A), Zn (B) and Mg (C) against Fe 2+  for <span class="search-highlight">tuhualite</span>. (D) Na plo...
Published: 01 March 2018
Fig. 3 Plots of Mn (A), Zn (B) and Mg (C) against Fe 2+ for tuhualite. (D) Na plotted against K. Analyses of K-rich, Na-poor regions in altered crystals have been omitted from (D). Data from Table S2A.
Image
BSE image and element distribution maps for a partially altered <span class="search-highlight">tuhualite</span> c...
Published: 01 March 2018
Fig. 4 BSE image and element distribution maps for a partially altered tuhualite crystal. Note the inverse relationship between Na and K, probably due to interaction with low-temperature fluids. The bright inclusions are aegirine. Data from ST1A, nos. 81–99.
Image
The view of a fragment of the <span class="search-highlight">tuhualite</span> structure viewed down the  a  axis,...
Published: 01 September 2001
F igure 1. The view of a fragment of the tuhualite structure viewed down the a axis, based on the structural data of Merlino (1969) . A zigzag-like chain of Fe 3+ octahedra and distorted, edge-shared Fe 2+ tetrahedra is parallel to the c axis. Six-coordinated Na + ions are located
Image
Polarized optical absorption spectrum of <span class="search-highlight">tuhualite</span> normalized to 1.0 cm thi...
Published: 01 September 2001
F igure 2. Polarized optical absorption spectrum of tuhualite normalized to 1.0 cm thickness. Individual bands labeled a through d are discussed in the text. ········ = E || a = α; ----- = E || b = β; —— = E || c = γ.
Journal Article
Published: 01 March 2016
European Journal of Mineralogy (2016) 28 (1): 153–161.
...+ . Single-crystal X-ray diffraction of Washington Pass brannockite confirms the space group P 6/ mcc with unit-cell parameters a = 10.014(2) Å, c = 14.268(5) Å, and V = 1239.16(8) Å 3 . Washington Pass brannockite co-exists with its Zr-analogues, both the milarite-group sogdianite and the related tuhualite...
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Journal Article
Published: 01 April 1978
American Mineralogist (1978) 63 (3-4): 304–310.
...) tetrahedra are 1.614, 1.616, and 1.610A. The Si-O-Si bond angles involving oxygens lying on mirror planes average 155.7°, whereas those within the single silicate chain average 147.6°. The larger Si-O-Si angles are associated with shorter Si-О bonds. Zektzerite is isostructural with tuhualite, (Na,K)Fe 2+ Fe...
Image
( a ,  b ,  c ) Tetrahedral representation of the   3 T 12   ribbon in  tuh...
Published: 26 February 2020
Fig. 46. ( a , b , c ) Tetrahedral representation of the 3 T 12 ribbon in tuhualite projected ( a ) onto (010), ( b ) orthogonal to the c -axis, ( c ) along the c -axis, ( d ) a ball-and-stick and ( e ) a graphical representation of the ribbon. Dashed black lines outline the geometrical
Image
Plot of the barycenter energy of the spin-allowed  dd  bands of  IV Fe 2+  ...
Published: 01 September 2001
), cordierite (Cord), osumilite (Osum), and tuhualite (Tuh). The points for beryl, cordierite, and osumilite are above the trend observed for the other minerals.
Journal Article
Published: 01 August 2004
The Canadian Mineralogist (2004) 42 (4): 1005–1011.
... minerals. An extended (or elpidite) chain was described in crystal structures of elpidite, Na 2 Zr [Si 6 O 15 ] (H 2 O) 3 ( Cannillo et al. 1973 ) and epididymite, Na 2 Be 2 [Si 6 O 15 ] (H 2 O) ( Pobedimskaya & Belov 1956 ). A kinked (or tuhualite) chain was described in the crystal structures...
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Journal Article
Published: 01 April 2003
The Canadian Mineralogist (2003) 41 (2): 513–520.
... ) atoms in the crystal structure of shibkovite, and (d) [Si 12 O 30 ] units and [12]-coordinated C (= K) atoms in the crystal structure of shibkovite. The minerals of the tuhualite group contain a silicate unit of the same stoichiometry as that in moskvinite-(Y): emeleusite, Na Na Li Fe 3...
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Journal Article
Published: 17 November 2015
The Canadian Mineralogist (2015) 53 (3): 455–460.
... PbO 16.17 14.75–18.77 1.19 PbCrO 4 Ce 2 O 3 4.29 3.76–5.41 0.49 monazite La 2 O 3 1.65 1.37–1.93 0.17 monazite Nd 2 O 3 0.41 0.00–0.62 0.18 monazite Y 2 O 3 0.42 0.17–0.67 0.16 Y 3 Al 5 O 12 SiO 2 0.03 0.00–0.09 0.03 tuhualite TiO 2 1.36 0.72–1.91...
FIGURES
Journal Article
Published: 01 May 2007
American Mineralogist (2007) 92 (5-6): 753–760.
...+ in adjacent octahedral sites ( Burns 1993 ), may be due to the fact that in our case the charge-transfer process takes place between Fe 2+ and Fe 3+ ions in non-equivalent, dodecahedral and octahedral sites of the garnet structure. A similar situation is found in cordierite or tuhualite, where energies...
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Journal Article
Published: 01 August 2006
Mineralogical Magazine (2006) 70 (4): 405–418.
... and Wuensch (1997) discuss the topology of M Si 6 O 15 structures, many of which contain topologically different silicate layers from that of sazhinite. The majority of the M Si 6 O 15 compounds are double-chain silicates [emeleusite, NaNaLiFe 3+ [Si 6 O 15 ], Upton et al. 1978 ; tuhualite, Na Fe 2...
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