IMA 2021-086 = gurzhiite

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Marco E. Ciriotti
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IMA 2021-086 = gurzhiite

Messaggio da Marco E. Ciriotti » ven 13 mag, 2022 10:29

Prossima pubblicazione.

Referenza:
▪ Kasatkin, A.V., Plášil, J., Chukanov, N.V., Škoda, R., Nestola, F., Agakhanov, A.A., Belakovskiy, D.I. (2022): Gurzhiite, Al(UO2)(SO4)2F⋅10H2O, a new uranyl sulfate mineral with chain structure from Bykogorskoe deposit, Northern Caucasus, Russia. Mineralogical Magazine, 86, (in press).

Abstract:
Gurzhiite, ideally Al(UO2)(SO4)2F·10H2O, is a new uranyl sulfate mineral from the Bykogorskoe U deposit, Northern Caucasus, Russia. It occurs as fine-grained aggregates forming veinlets up to 50 cm long in cracks of the brecciated rock. Gurzhiite aggregates are composed of small bladed crystals up to 0.1 mm across. Associated minerals include khademite and quartz. Gurzhiite is pale yellow in crystals, lemon yellow in aggregates, transparent with vitreous lustre and white streak. It is brittle and has an irregular fracture. Cleavage is good on {001}. The new mineral exhibits a bright yellow-green fluorescence under both longwave and shortwave UV radiation. Mohs hardness is ~2. Dmeas = 2.52(3) g/cm3, Dcalc = 2.605 g/cm3. The mineral is biaxial (–) with α = 1.528(3), β = 1.538(2), γ = 1.544(3) (589 nm); 2Vmeas= 80(10), 2Vcalc = 75.1. The empirical formula calculated on the basis of 21(O + F) apfu is Al0.92Zn0.05Fe3+0.03Na0.03U0.95S2.00O9.85F0.99 · 10.16H2O. Gurzhiite is triclinic, space group P–1, a = 7.193(2), b = 11.760(2), c = 11.792(2) Å, α = 67.20(3), β = 107.76(3), γ = 89.99(3)°, V = 867.7(4) Å3 and Z = 2. The five strongest lines of the powder X-ray diffraction pattern [d, Å (I, %)(hkl)] are: 10.24(100)(001); 5.40(14)(-1-11); 5.11(54)(002); 3.405(11)(-211); 3.065(11)(-1-13). The crystal structure of gurzhiite is based upon uranyl-sulfate chains of the same type as have been found e.g., in. bobcookite or svornostite. Between the chains are two types of Al-octahedra – Al1(H2O)6 and Al2F2(H2O)4. The entire structure is held by a complex network of H-bonds. The new mineral honors Russian mineralogist and crystallographer Dr. Vladislav V. Gurzhiy in recognition for his contributions to uranium mineralogy and crystallography.

NdR: Chemically very similar to straßmannite, but structurally different.
Bobcookite group
Bobcookite NaAl(UO2)2(SO4)4·18H2O
Gurzhiite Al(UO2)(SO4)2F∙10H2O
Oldsite K2Fe2+[(UO2)(SO4)2]2(H2O)8
Oppenheimerite Na2(UO2)(SO4)2·3H2O
Rietveldite Fe2+(UO2)(SO4)2(H2O)5
Svornostite K2Mg[(UO2)(SO4)2]2∙8H2O
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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Marco E. Ciriotti
Messaggi: 31645
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2021-086 = gurzhiite

Messaggio da Marco E. Ciriotti » gio 11 ago, 2022 3:53

Pubblicazione effettuata.

Referenza:
▪ Kasatkin, A.V., Plášil, J., Chukanov, N.V., Škoda, R., Nestola, F., Agakhanov, A.A., Belakovskiy, D.I. (2022): Gurzhiite, Al(UO2)(SO4)2F⋅10H2O, a new uranyl sulfate mineral with chain structure from Bykogorskoe deposit, Northern Caucasus, Russia. Mineralogical Magazine, 86, 412-421.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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