IMA 2016–068 = calciojohillerite

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Marco E. Ciriotti
Messaggi: 28032
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
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IMA 2016–068 = calciojohillerite

Messaggio da Marco E. Ciriotti » ven 15 gen, 2021 10:47

Prossima pubblicazione.

Referenza:
▪ Pekov, I.V., Koshlyakova, N.N.,, Agakhanov, A.A., Zubkova, N.V., Belakovskiy, D.I., Vigasina, M.F., Turchkova, A.G., Sidorov, E.G., Pushcharovsky, D.Yu. (2021): New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XV. Calciojohillerite, NaCaMgMg2(AsO4)3, a member of the alluaudite group. Mineralogical Magazine, 85, (in press).

Abstract:
The new alluaudite-group mineral сalciojohillerite is one of the major arsenates in sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. In middle zones of the fumarole, calciojohillerite is associated with hematite, tenorite, johillerite, nickenichite, bradaczekite, badalovite, tilasite, lammerite, ericlaxmanite, aphthitalite-group sulfates, langbeinite, calciolangbeinite, anhydrite, sanidine, fluorophlogopite, fluoborite, cassiterite, pseudobrookite, rutile, sylvite and halite. In deep zones it occurs in association with anhydrite, diopside, hematite, svabite, berzeliite, schäferite, forsterite, magnesioferrite, ludwigite, rhabdoborite-group fluoroborates, powellite, baryte, fluorapatite, udinaite, arsenudinaite and paraberzeliite. Calciojohillerite forms prismatic crystals up to 1 cm long, their aggregates and crystal crusts up to 0.5 m2. It is transparent, colourless, pale green, pale yellow, light blue, pale lilac or pink, with vitreous lustre. The mineral is brittle, with imperfect cleavage. The Mohs hardness is 3½. Dcalc is 3.915 g cm-3. Calciojohillerite is optically biaxial (–), α = 1.719(3), β = γ = 1.732(3); 2Vmeas. = 15(10)º. Chemical composition (wt%, electron-microprobe; holotype) is: Na2O 7.32, K2O 0.10, CaO 6.82, MgO 20.31, MnO 0.68, CuO 0.27, ZnO 0.02, Al2O3 0.56, Fe2O3 3.53, TiO2 0.01, SiO2 0.03, P2O5 1.25, V2O5 0.10, As2O5 58.77, SO3 0.13, total 99.90. The empirical formula based on 12 O atoms is (Na1.30K0.01Ca0.67Mg2.78Mn0.05Cu0.02Al0.06Fe3+0.24)Σ5.13(As2.83P0.10S0.01V0.01)Σ2.95O12. Calciojohillerite is monoclinic, C2/c, a = 11.8405(3), b = 12.7836(2), c = 6.69165(16) Å, β = 112.425(3)º, V = 936.29(4) Å3 and Z = 4. The crystal structure was solved from single-crystal X-ray diffraction data, R = 0.0227. Calciojohillerite is isostructural with other alluaudite-group minerals. Its simplified crystal chemical formula is A(1)CaA(1)’□A(2)□A(2)’NaM(1)MgM(2)Mg2(AsO4)3 (□ = vacancy). The idealized formula is NaCaMg3(AsO4)3, or, according to the nomenclature of alluaudite-group arsenates, NaCaMgMg2(AsO4)3. Calciojohillerite is named as an analogue of johillerite NaCu2+MgMg2(AsO4)3 with species-defining Ca instead of Cu in the ideal formula.
Marco E. Ciriotti

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

Avatar utente
Marco E. Ciriotti
Messaggi: 28032
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2016–068 = calciojohillerite

Messaggio da Marco E. Ciriotti » dom 18 apr, 2021 10:54

Pubblicazione effettuata.

Referenza:
▪ Pekov, I.V., Koshlyakova, N.N.,, Agakhanov, A.A., Zubkova, N.V., Belakovskiy, D.I., Vigasina, M.F., Turchkova, A.G., Sidorov, E.G., Pushcharovsky, D.Yu. (2021): New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XV. Calciojohillerite, NaCaMgMg2(AsO4)3, a member of the alluaudite group. Mineralogical Magazine, 85, 215-223.
Marco E. Ciriotti

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

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