New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XV. Calciojohillerite, NaCaMgMg₂(AsO₄)₃, a member of the alluaudite group

Abstract

The new alluaudite-group mineral calciojohillerite 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)°. 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)°, V = 936.29(4) Å3 and Z = 4. The crystal structure was solved from single-crystal X-ray diffraction data, R1 = 0.0227. Calciojohillerite is isostructural with other alluaudite-group minerals. Its simplified crystal chemical formula is A (1)Ca A (1)′□ A (2)□ A (2)′Na M (1)Mg M (2)Mg2(AsO4)3 (□ = vacancy). The idealised 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.

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

“…Some specimens of paraberzeliite contain up to 0.4 apfu Mn (Table 1, #2) and the existence of a hypothetical isomorphous series between caryinite and paraberzeliite is possible, such as is known for the reported from Långban series between berzeliite (Ca 2 Na)Mg 2 (AsO 4 ) 3 and manganberzeliite (Ca 2 Na)Mn 2 (AsO 4 ) 3 (Holtstam and Langhof, 1999), the arsenate garnets dimorphous with these alluaudite-group minerals. A related pair of alluaudite-group minerals, arseniopleite NaCaMn 3 (AsO 4 ) 3 (the sample from the Långban-type deposit Sjö in Sweden was studied: Tait and Hawthorne, 2003) and calciojohillerite NaCaMg 3 (AsO 4 ) 3 (from the Arsenatnaya fumarole: Pekov et al, 2021a), demonstrates the same features of A Ca distribution: their simplified structural formulae are A(1)'' Ca A(2)' Na M(1) Mn M(2) Mn 2 (AsO 4 ) 3 and A(1) Ca A(2)' Na M(1) Mg M(2) Mg 2 (AsO 4 ) 3 , respectively.…”

“…In this paper, we continue the characterisation of new arsenate mineral species found in the Arsenatnaya fumarole located at the apical part of the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption 1975–1976, Tolbachik volcano, Kamchatka Peninsula, Far-Eastern Region, Russia (55°41′N, 160°14′E, 1200 m a.s.l.). Nineteen new minerals have been described in the previous articles of this 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), and yurgensonite K 2 SnTiO 2 (AsO 4 ) 2 (Pekov et al , 2021b).…”

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

“…Intensity data were corrected for Lorentz and polarisation effects. The crystal structure of the new mineral was refined using the calciojohillerite structure (Pekov et al, 2021a) as the starting model with the SHELX software package (Sheldrick, 2015) to R = 0.0287 on the T(1)O 4 tetrahedra share all vertices with the M-centred octahedra to form the (010) heteropolyhedral layers (Fig. 3b) whereas each T(2)O 4 tetrahedron shares three vertices with the MO 6 octahedra of one layer and the fourth vertex with the octahedron of the adjacent layer, thus linking the layers to a three-dimensional framework.…”

“…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, 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. XVI. Yurgensonite, K2SnTiO2(AsO4)2, the first natural tin arsenate, and the katiarsite–yurgensonite isomorphous series

“…This paper continues the series of articles devoted to new arsenate minerals discovered in the active Arsenatnaya fumarole located at the apical part of the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption 1975-1976 Region, Russia (55°41 ′ N 160°14 ′ E, 1200 m a.s.l.). Eighteen new species were described in previous articles of this series, namely yurmarinite Na 7 (Fe 3+ ,Mg,Cu) 4 (AsO 4 ) 6 (Pekov et al, 2014a), ericlaxmanite and kozyrevskite, two polymorph modifications of Cu 4 O(AsO 4 ) 2 (Pekov et al, 2014b), popovite Cu 5 O 2 (AsO 4 ) 2 (Pekov et al, 2015a), shchurovskyite K 2 CaCu 6 O 2 (AsO 4 ) 4 and dmisokolovite K 3 Cu 5 AlO 2 (AsO 4 ) 4 related to one another in terms of crystal chemistry (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, 2018b), arsenatrotitanite NaTiO(AsO 4 ) (Pekov et al, 2019a), edtollite K 2 NaCu 5 Fe 3+ O 2 (AsO 4 ) 4 and its Al-dominant analogue 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) and calciojohillerite NaCaMgMg 2 (AsO 4 ) 3 (Pekov et al, 2021).…”