New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XVII. Paraberzeliite, NaCaCaMg₂(AsO₄)₃, an alluaudite-group member dimorphous with berzeliite

Abstract

The new alluaudite-group mineral parabezeliite was found in the Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. In the deepest zone of Arsenatnaya, paraberzeliite (holotype) is accociated with anhydrite, diopside, hematite, svabite, berzeliite, schäferite, calciojohillerite, magnesioferrite, ludwigite, fluorapatite, powellite, baryte, and rhabdoborite-group and aphthitalitegroup members. In the middle zone of the fumarole, paraberzeliite occurs with hematite, calciojohillerite, badalovite, johillerite, nickenichite, tilasite, svabite, fluorophlogopite, sanidine, cassiterite, anhydrite, metathénardite and belomarinaite. Paraberzeliite forms prismatic crystals up to 0.2 × 0.2 × 1 mm 3 often occurring in open-work aggregates. It is transparent, brown (from light to dark brown, sometimes with purple or red hue) or green (from pale greenish to yellow-green).The mineral is brittle, cleavage was not observed. The Mohs hardness is 3½. D calc is 3.811 g cm -3 .Paraberzeliite is optically biaxial (+), α = 1.718(4), β = 1.728(4), γ = 1.742(4), 2V meas. = 85( 5)º. The chemical composition (wt.%, electron-microprobe; holotype) is: Na 2 O 6.43, CaO 16.65, MgO 11.64, MnO 1.65, CuO 0.06, Fe 2 O 3 2.45, V 2 O 5 1.10, As 2 O 5 59.46, total 99.44. The calculated empirical formula based on 12 O atoms per formula unit is (Na 1.20 Ca 1.71 Mg 1.66 Mn 0.13 Fe 3+ 0.18 ) Σ4.88 (As 2.98 V 0.07 ) Σ3.05 O 12 . Paraberzeliite is monoclinic, C2/c, a = 12.3143( 7), b = 13.0679( 5), c = 6.7717(4) Å, β = 113.657(7)º, V = 998.14(10) Å 3 and Z = 4. The crystal structure was solved from single-crystal X-ray diffraction data, R = 0.0349. Paraberzeliite is isostructural with other alluaudite-group minerals. Its simplified crystal chemical formula is A(1) Ca A(2)' Na M(1) Ca M(2) Mg 2 ( T AsO 4 ) 3 . The idealized formula is NaCa 2 Mg 2 (AsO 4 ) 3 , or, according to the actual nomenclature of alluaudite-group arsenates, NaCaCaMg 2 (AsO 4 ) 3 . The name paraberzeliite reflects the dimorphism of this alluaudite-group mineral with the arsenate garnet berzeliite, ideally (Ca 2 Na)Mg 2 (AsO 4 ) 3 .

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XX. Evseevite, Na2Mg(AsO4)F, the first natural arsenate with an antiperovskite structure

“…This paper continues the series of articles in which we characterise new arsenates from the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption 1975–1976, Tolbachik volcano, Kamchatka Peninsula, Far-Eastern Region, Russia. Twenty two new mineral species have been described in the previous papers of the series: yurmarinite Na 7 (Fe 3+ ,Mg,Cu) 4 (AsO 4 ) 6 (Pekov et al , 2014a), two polymorphs of Cu 4 O(AsO 4 ) 2 , ericlaxmanite and kozyrevskite (Pekov et al , 2014b), popovite Cu 5 O 2 (AsO 4 ) 2 (Pekov et al , 2015b), structurally related shchurovskyite K 2 CaCu 6 O 2 (AsO 4 ) 4 and dmisokolovite K 3 Cu 5 AlO 2 (AsO 4 ) 4 (Pekov et al , 2015a), katiarsite KTiO(AsO 4 ) (Pekov et al , 2016b), melanarsite K 3 Cu 7 Fe 3+ O 4 (AsO 4 ) 4 (Pekov et al , 2016a), pharmazincite KZnAsO 4 (Pekov et al , 2017), arsenowagnerite Mg 2 (AsO 4 )F (Pekov et al , 2018b), arsenatrotitanite NaTiO(AsO 4 ) (Pekov et al , 2019d), the two isostructural minerals edtollite K 2 NaCu 5 Fe 3+ O 2 (AsO 4 ) 4 and alumoedtollite K 2 NaCu 5 AlO 2 (AsO 4 ) 4 (Pekov et al , 2019e), anatolyite Na 6 (Ca,Na)(Mg,Fe 3+ ) 3 Al(AsO 4 ) 6 (Pekov et al , 2019b), zubkovaite Ca 3 Cu 3 (AsO 4 ) 4 (Pekov et al , 2019a), pansnerite K 3 Na 3 Fe 3+ 6 (AsO 4 ) 8 (Pekov et al , 2020c), badalovite NaNaMg(MgFe 3+ )(AsO 4 ) 3 (Pekov et al , 2020b), calciojohillerite NaCaMgMg 2 (AsO 4 ) 3 (Pekov et al , 2021a), yurgensonite K 2 SnTiO 2 (AsO 4 ) 2 (Pekov et al , 2021b), paraberzeliite NaCaCaMg 2 (AsO 4 ) 3 (Pekov et al , 2022a), khrenovite Na 3 Fe 3+ 2 (AsO 4 ) 3 (Pekov et al , 2022b), and axelite Na 14 Cu 7 (AsO 4 ) 8 F 2 Cl 2 (Pekov et al , 2023).…”

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XVIII. Khrenovite, Na3Fe3+2(AsO4)3, the member with the highest sodium in the alluaudite supergroup

“…This paper continues the series of descriptions of new arsenate mineral species found in the Arsenatnaya fumarole situated at the apical part of the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption 1975–1976 (NB GTFE), Tolbachik volcano, Kamchatka Peninsula, Far-Eastern Region, Russia (55°41'N 160°14'E, 1200 m a.s.l.). Twenty new minerals have been characterised in the previous papers of the series: yurmarinite Na 7 (Fe 3+ ,Mg,Cu) 4 (AsO 4 ) 6 (Pekov et al , 2014a), two polymorphs of Cu 4 O(AsO 4 ) 2 , ericlaxmanite and kozyrevskite (Pekov et al , 2014b), popovite Cu 5 O 2 (AsO 4 ) 2 (Pekov et al , 2015a), structurally related shchurovskyite K 2 CaCu 6 O 2 (AsO 4 ) 4 and dmisokolovite K 3 Cu 5 AlO 2 (AsO 4 ) 4 (Pekov et al , 2015b), katiarsite KTiO(AsO 4 ) (Pekov et al , 2016a), melanarsite K 3 Cu 7 Fe 3+ O 4 (AsO 4 ) 4 (Pekov et al , 2016b), pharmazincite KZnAsO 4 (Pekov et al , 2017), arsenowagnerite Mg 2 (AsO 4 )F (Pekov et al , 2018c), arsenatrotitanite NaTiO(AsO 4 ) (Pekov et al , 2019a), the two isostructural minerals edtollite K 2 NaCu 5 Fe 3+ O 2 (AsO 4 ) 4 and alumoedtollite K 2 NaCu 5 AlO 2 (AsO 4 ) 4 (Pekov et al , 2019b), anatolyite Na 6 (Ca,Na)(Mg,Fe 3+ ) 3 Al(AsO 4 ) 6 (Pekov et al , 2019c), zubkovaite Ca 3 Cu 3 (AsO 4 ) 4 (Pekov et al , 2019d), pansnerite K 3 Na 3 Fe 3+ 6 (AsO 4 ) 8 (Pekov et al , 2020a), badalovite NaNaMg(MgFe 3+ )(AsO 4 ) 3 (Pekov et al , 2020b), calciojohillerite NaCaMgMg 2 (AsO 4 ) 3 (Pekov et al , 2021a), yurgensonite K 2 SnTiO 2 (AsO 4 ) 2 (Pekov et al , 2021b) and paraberzeliite NaCaCaMg 2 (AsO 4 ) 3 (Pekov et al , 2022).…”

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XIX. Axelite, Na14Cu7(AsO4)8F2Cl2

“…The present article continues the series of papers devoted to descriptions of new arsenates from the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption 1975–1976, Tolbachik volcano, Kamchatka Peninsula, Far-Eastern Region, Russia. Twenty one new minerals were characterised in the previous papers of the series, namely yurmarinite Na 7 (Fe 3+ ,Mg,Cu) 4 (AsO 4 ) 6 (Pekov et al , 2014a), two polymorphs of Cu 4 O(AsO 4 ) 2 , ericlaxmanite and kozyrevskite (Pekov et al , 2014b), popovite Cu 5 O 2 (AsO 4 ) 2 (Pekov et al , 2015a), structurally related shchurovskyite K 2 CaCu 6 O 2 (AsO 4 ) 4 and dmisokolovite K 3 Cu 5 AlO 2 (AsO 4 ) 4 (Pekov et al , 2015b), katiarsite KTiO(AsO 4 ) (Pekov et al , 2016a), melanarsite K 3 Cu 7 Fe 3+ O 4 (AsO 4 ) 4 (Pekov et al , 2016b), pharmazincite KZnAsO 4 (Pekov et al , 2017a), arsenowagnerite Mg 2 (AsO 4 )F (Pekov et al , 2018b), arsenatrotitanite NaTiO(AsO 4 ) (Pekov et al , 2019a), the two isostructural minerals edtollite K 2 NaCu 5 Fe 3+ O 2 (AsO 4 ) 4 and alumoedtollite K 2 NaCu 5 AlO 2 (AsO 4 ) 4 (Pekov et al , 2019b), anatolyite Na 6 (Ca,Na)(Mg,Fe 3+ ) 3 Al(AsO 4 ) 6 (Pekov et al , 2019c), zubkovaite Ca 3 Cu 3 (AsO 4 ) 4 (Pekov et al , 2019d), pansnerite K 3 Na 3 Fe 3+ 6 (AsO 4 ) 8 (Pekov et al , 2020a), badalovite NaNaMg(MgFe 3+ )(AsO 4 ) 3 (Pekov et al , 2020b), calciojohillerite NaCaMgMg 2 (AsO 4 ) 3 (Pekov et al , 2021a), yurgensonite K 2 SnTiO 2 (AsO 4 ) 2 (Pekov et al , 2021b), paraberzeliite NaCaCaMg 2 (AsO 4 ) 3 (Pekov et al , 2022a) and khrenovite Na 3 Fe 3+ 2 (AsO 4 ) 3 (Pekov et al , 2022b).…”