IMA 2017-019 = vanadio-pargasite

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Marco E. Ciriotti
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IMA 2017-019 = vanadio-pargasite

Messaggio da Marco E. Ciriotti » sab 12 mag, 2018 9:57

Prossima pubblicazione.

Referenza:
▪ Cametti, G., Armbruster, T., Reznitsky, L.Z., Sklyarov, E.V., Della Ventura, G. (2018): Crystal structure and crystal-chemistry of vanadio-pargasite: a new amphibole from southern Lake Baikal, Siberia, Russia. European Journal of Mineralogy, 30, (in press).

Abstract:
The crystal structure of a new member of the calcium amphibole subgroup, vanadio-pargasite ideally NaCa2(Mg4V3+) Si6Al2O22(OH)2 with empirical formula (K0.07Na0.90)(Na0.05Ca1.91Mg0.04)Σ2.00(Mg4.02Cr0.05V0.68Al0.23Ti0.02)Σ5.00(Si6.09Al1.91)Σ8.00O22(OH1.67F0.33)Σ2.00, was studied by single-crystal X-ray diffraction and refined to R1 of 0.0181. It is monoclinic, space group C2/m, unit-cell parameters a = 9.8956(1), b = 17.9970(2), c = 5.2970(1)Å, β = 105.391(1)°, and V = 909.52Å3. The mineral is isostructural with the amphiboles pargasite, magnesio-hastingsite, chromio-pargasite and Mn3+-rich pargasite. Site populations were derived from the structure refinement and electron-microbe analysis, and validated on the basis of OH-stretching FTIR spectroscopy. Accordingly, V is ordered at M(2) together with minor [6]Al, while a low amount of [6]Al is present at M(3).
Marco E. Ciriotti

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

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Marco E. Ciriotti
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Iscritto il: ven 25 giu, 2004 11:31
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Re: IMA 2017-019 = vanadio-pargasite

Messaggio da Marco E. Ciriotti » mer 07 nov, 2018 22:02

Pubblicazione effettuata.

Referenza:
▪ Cametti, G., Armbruster, T., Reznitsky, L.Z., Sklyarov, E.V., Della Ventura, G. (2018): Crystal structure and crystal-chemistry of vanadio-pargasite: a new amphibole from southern Lake Baikal, Siberia, Russia. European Journal of Mineralogy, 30, 981-987.
Marco E. Ciriotti

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TOSATO FABIO
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Re: IMA 2017-019 = vanadio-pargasite

Messaggio da TOSATO FABIO » gio 08 nov, 2018 7:39

COMPLIMENTI A TUTTI.
Tosato Fabio
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Noi siamo anche quello che non siamo riusciti ad essere.
Sic transit gloria mundi.

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Marco E. Ciriotti
Messaggi: 25339
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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Re: IMA 2017-019 = vanadio-pargasite

Messaggio da Marco E. Ciriotti » ven 05 apr, 2019 11:05

Referenza:
▪ Reznitsky, L.Z., Sklyarov, E.V., Cametti, G., Armbruster, T., Suvorova, L.F., Ushchapovskaya, Z.F., Barash, I.G. (2018): Vanadio-pargasite NaCa2(Mg4V)(Si6Al2)O22(OH)2: a New Mineral of the Amphibole Supergroup. Geology of Ore Deposits, 60, 607-615.

Abstract:
A new mineral was discovered in Cr–V-bearing marbles of the Sludyanka Complex from the Pereval marble quarry, Sludyanka district, southern Baikal region, Russia. It was named vanadio-pargasite as vanadium-bearing analog of pargasite according to the amphibole supergroup classification and CNMNC recommendations. Black Cr–V-spinel (magnesiocoulsonite–magnesiochromite), red Cr–V-bearing spinel, calcite, dolomite, Cr–V-bearing diopside and chlorite, phlogopite, and forsterite are associated minerals. Vanadio-pargasite occurs as subhedral long- and short-prismatic crystals 0.10–0.8 × 0.05–0.10 mm in size, with (110) and (010) faces and perfect cleavage by (110). Macroscopically, the new mineral is bright green to emerald green with vitreous luster; in thin sections and powder, it is pale green, without pleochroism. The new mineral is biaxial, positive, 2V = 86° ± 2°, γ = 1.659(2), β = 1.651(2), α = 1.643(2). The Mohs hardness is ~ 6, average VHN50;100 is 795; range 752–824 kg/mm2. The measured and calculated density is 3.05(5) and 3.112 g/cm3, respectively. In a thermogram over the range 654–1081°С, H2O is released with a endothermic effect. Over the range 900–1183°C, the main endothermic effect is caused by water and, possibly, F release, as well as melting of the mineral (1020°C). The absorption bands in the IR spectrum are, cm–1: 3445, 1633, 980, and 469. Vanadio-pargasite is monoclinic, space group C2/m; the unit cell parameters are: a = 9.914(3), b = 18.003(2), c = 5.300(2) Å, β = 105.69(3)°, V = 910.7(5) Å3, Z = 2. The strongest reflections in the X-ray diffraction pattern are [d, Å (I) (hkl)]: 8.98 (15) (020), 8.43 (40) (110), 3.27 (30) (240), 3.14 (100) (310), 2.82 (35) (330), 2.70 (18) (151), 2.34 (15) (421), 1.898 (15) (510), 1.445 (25) (4.101). The average chemical composition (528 point analyses) is, wt %: 42.75 SiO2, 0.14 TiO2, 12.75 A12O3, 0.44 Cr2O3, 5.92 V2O3, 19.15 MgO, 0.03 FeO, 0.01 MnO, 12.52 CaO, 3.45 Na2O, 0.41 K2O, 0.74 F (wet chem.) 1.75 H2O (calc.); the total is 99.91. The simplified formula is K0.1Na0.9Ca2.0Mg4.0V0.7Al0.3(Si6.1Al1.9)8.0O22(OH1.7F0.3)2.0. Holotype material has been deposited at the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia (registration nos. 5035/1, 5035/2, and 5035/3).
Marco E. Ciriotti

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