The new ludwigite-group mineral savelievaite, ideally Mg2Cr3+O2(BO3), was found in the chromitite body at the Malaya Kharamatalou river valley, Voikar–Syninskiy ultrabasic complex, Polar Urals, Russia. Savelievaite and Cr-enriched ludwigite occur in clinochlore veinlets and are associated with earlier magnesiochromite, spinel, chromite, pargasite, diopside, forsterite, serpentine, magnetite and pentlandite. Savelievaite forms prismatic, acicular or fibrous crystals up to 0.05 × 0.4 mm, usually assembled in radiating or chaotic clusters up to 1 × 1.5 mm across. It is opaque, black to greenish-black. The lustre is vitreous for prismatic crystals and silky for fibrous aggregates. D(calc.) = 3.91 g cm–3. Under the microscope in reflected light, savelievaite is grey, non-pleochroic, with weak bireflectance and anisotropism. The chemical composition (wt.%, EMPA, Fe2+:Fe3+ ratio by stoichiometry) is: MgO 34.88, FeO 10.83, NiO 0.36, B2O3 16.80, Al2O3 2.97, V2O3 0.21, Cr2O3 21.97, Fe2O3 12.40, TiO2 0.43, total 100.85. The empirical formula calculated on the basis of 5 O apfu is (Mg1.72Fe2+0.30Ni0.01)Σ2.03(Cr3+0.57Fe3+0.31Al0.12Ti0.01V3+0.01)Σ1.02B0.96O5. Savelievaite is orthorhombic, space group Pbam, a = 9.2631(6), b = 12.2298(8), c = 3.0104(2) Å, V = 341.04(4) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 5.101(100)(120); 2.551(90)(240); 2.524(88)(201); 2.163(36)(250); and 2.033(55)(321). The crystal structure was solved from single-crystal X-ray diffraction data and refined to R1 = 0.0405. Savelievaite is isostructural with ludwigite, Cr3+ is concentrated at the M4 site. The mineral is named in honour of the Russian petrologist and geologist Dr. Galina Nikolaevna Savelieva (b. 1936). Ludwigite, ideally Mg2Fe3+O2(BO3), and savelievaite form a continuous isomorphous series in which Cr3+ content varies from 0 to 0.60 apfu. Occurrences of Cr-enriched (>1 wt.% Cr2O3) varieties of ludwigite are mainly related to ultrabasic complexes. The Cr-richest (>10 wt.% Cr2O3) ludwigite–savelievaite-series members are found in chromite ores at the Voikar–Syninskiy complex and Volchiegorskoe and Tatishchevskoe deposits, both in the South Urals.

The new mineral evseevite was found in the Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. Evseevite is represented by two chemical varieties. The variety close to the end-member Na2Mg(AsO4)F (holotype) is associated with sanidine, hematite, tenorite, aegirine, cassiterite, sylvite, halite, johillerite, badalovite, calciojohillerite, hatertite, arsmirandite, yurmarinite, axelite, polyarsite, aphthitalite, potassic-magnesio-fluoro-arfvedsonite, litidionite, ferrisanidine and tridymite. The P- and S-enriched variety (cotype) is associated with hematite, fluorophlogopite, svabite, fluorapatite, tilasite, calciojohillerite, forsterite, cassiterite, belomarinaite and aphthitalite. Evseevite occurs as prismatic, acicular or hair-like crystals up to 0.7 mm long combined in clusters up to 0.5 mm, brushes or crusts up to 2 × 2 mm. It is transparent, colourless or pale pinkish, with vitreous lustre. Dcalc is 3.377 g cm–3 for the holotype and 3.226 g cm–3 for the cotype. Evseevite is optically uniaxial (+), α = 1.545(2), β = 1.546(2), γ = 1.549(2) and 2Vmeas = 40(10)°. The empirical formulae calculated based on O+F = 5 apfu are (Na1.99Ca0.03K0.01)Σ2.03(Mg0.98Fe3+0.01Zn0.01Cu0.01)Σ1.01[(As0.98Si0.01)Σ1.01O4](F0.97O0.03) for the holotype and Na2.02(Mg1.00Fe3+0.03)Σ1.03[(As0.69P0.25S0.07)Σ1.01O4](F0.78O0.22) for the cotype. Evseevite is orthorhombic, Pbcn, a = 5.3224(1), b = 14.1255(3), c = 12.0047(3) Å, V = 902.53(4) Å3 and Z = 8. Strong reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 4.001(100)(121), 3.479(56)(023), 3.041(45)(042), 2.657(44)(200), 2.642(68)(142) and 2.613(36)(104). The crystal structure was solved from single-crystal XRD data and refined on powder data by the Rietveld method, Rwp = 0.0068, Rp = 0.0047 and Robs = 0.0435. Evseevite is isostructural to moraskoite Na2Mg(PO4)F. The structure of evseevite can be described in terms of anion-centred polyhedra. F-centred octahedra [FNa4Mg2]7+ share faces to form chains [FNa2Mg]3+ and AsO4 tetrahedra are located between the chains. Evseevite belongs to a small set of minerals with antiperovskite structures and is the first natural arsenate with antiperovskite units. The mineral is named in honour of the Russian mineralogist Aleksandr Andreevich Evseev (born 1949).

The new mineral bakakinite, ideally Ca2V2O7, was found in the high-temperature (not lower than 500°C) exhalations of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with anhydrite, svabite, pliniusite, schäferite, berzeliite, diopside, hematite, powellite, baryte, fluorapatite, calciojohillerite, ludwigite, magnesioferrite, anorthite, titanite and esseneite. Bakakinite forms flattened crystals up to 30 × 5 μm, typically distorted. The mineral is transparent, colourless or pale yellow, with strong vitreous lustre. Electron microprobe analysis gave (wt.%): CaO 37.04, SrO 0.26, SiO2 0.16, P2O5 1.48, V2O5 49.47, As2O5 10.85, SO3 0.35, total 99.61. The empirical formula calculated on the basis of 7 O apfu is (Ca1.99Sr0.01)Σ2.00(V1.64As0.28P0.06Si0.01S0.01)Σ2.00O7. The Dcalc is 3.463 g cm–3. Bakakinite is triclinic, P$\bar{1}$, unit-cell parameters are: a = 6.64(2), b = 6.92(2), c = 7.01(2) Å, α = 86.59(7), β = 63.77(7), γ = 83.47(6)°, V = 287.0(5) Å3 and Z = 2. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 4.647(27)(111, 0$\bar{1}$1), 3.138(76)(002), 3.103(100)(120, 121), 3.027(20)(021), 2.960(81)(200), 2.158(19)(031, 302), 1.791(16)(320), 1.682(16)(114) and 1.584(17)(1$\bar{3}$3, 403). Bakakinite is a natural analogue of synthetic Ca2V2O7. The mineral is named in honour of the outstanding Russian crystallographer and crystal chemist Vladimir Vasilievich Bakakin (born 1933).

The new mineral yurgensonite, ideally K2SnTiO2(AsO4)2, the first natural arsenate with species-defining tin, and the continuous isomorphous series between yurgensonite and katiarsite KTiO(AsO4) are described from sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. Yurgensonite and a Sn-bearing variety of katiarsite are associated closely with one another and with badalovite, pansnerite, yurmarinite, achyrophanite, arsenatrotitanite, hatertite, khrenovite, svabite, sanidine, hematite, cassiterite, rutile and aphthitalite-group sulfates. Yurgensonite occurs as sword-shaped crystals up to 0.01 mm × 0.05 mm × 1 mm or acicular to hair-like individuals up to 1 mm long, typically forming radial aggregates up to 2 mm across. It is transparent, colourless, white or pale beige, with vitreous lustre. The mineral is brittle, cleavage was not observed. Dcalc is 3.877 g cm-3. Yurgensonite is optically biaxial (–), α = 1.764(6), β = 1.780(6), γ = 1.792(6) and 2Vmeas. is large. Chemical composition (wt.%, electron-microprobe; holotype) is: Na2O 0.51, K2O 16.27, Rb2O 0.12, Al2O3 0.26, Fe2O3 4.33, SiO2 0.29, TiO2 10.17, SnO2 22.01, P2O5 0.14, V2O5 0.19, As2O5 40.20, Sb2O5 4.88, SO3 0.28, total 99.65. The empirical formula based on 10 O apfu is (K1.92Na0.09Rb0.01)Σ2.02(Sn0.81Ti0.71Fe3+0.30Sb5+0.17Al0.03)Σ2.02(As1.945Si0.03S0.02P0.01V0.01)Σ2.015O10. Yurgensonite is orthorhombic, Pna21, a = 13.2681(6), b = 6.6209(3), c = 10.8113(5) Å, V = 949.74(7) Å3 and Z = 4. The crystal structure was solved from single-crystal X-ray diffraction data, R = 5.02%. Yurgensonite belongs to the KTP-structure type. It is a Ti,Sn-ordered analogue of katiarsite. The structure contains chains of corner-linked alternating crystallographically non-equivalent octahedra M(1) and M(2). In yurgensonite, Sn4+ prevails in the M(2)O6 octahedron whereas the M(1) site is Ti4+-dominant. The new mineral is named in honour of the Russian mineralogist, geochemist and specialist in studies of ore deposits Professor Georgiy Aleksandrovich Yurgenson (born 1935).

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)CaA(1)′□A(2)□A(2)′NaM(1)MgM(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.

An unusual highly hydrated and Na-depleted variety of elpidite was identified in a hydrothermally altered peralkaline pegmatite at Mt. Yukspor in the Khibiny alkaline complex, Kola Peninsula, Russia. It differs from ‘ordinary’ elpidite, ideally Na2ZrSi6O15⋅3H2O, in its crystal chemical features, infrared spectrum and optical characteristics. The chemical composition (wt.%, electron microprobe, H2O by TGA) is: Na2O 5.45, K2O 0.67, CaO 0.05, SiO2 60.32, TiO2 1.34, ZrO2 18.43, Nb2O5 0.65, H2O 12.80, total 99.71. The empirical formula calculated on the basis of 6 Si and 15 O atoms is [(Na1.05K0.08Ca0.01)Σ1.14(H3O)0.74]Σ1.88(Zr0.89Ti0.10Nb0.03)Σ1.02Si6O15⋅3.47H2O; the H2O:H3O ratio was calculated from the charge balance requirement, taking into account the results of crystal structure refinement. The highly hydrated variety of elpidite is orthorhombic, Pma2, a = 14.5916(6), b = 7.3294(3), c = 7.1387(2) Å, V = 763.47(5) Å3 and Z = 2. The crystal structure was solved from single-crystal X-ray diffraction data, R1 = 3.43%. The structure is based upon an elpidite-type heteropolyhedral Zr–Si–O framework with Na+ and H3O+ cations and H2O molecules in the zeolitic channels. Hydronium cations substitute for water molecules in one of the extra-framework sites. This variety of elpidite could be considered as an intermediate product of natural ion-exchange reaction between ‘ordinary’ elpidite and a low-temperature hydrothermal fluid.

The new alluaudite-group mineral badalovite was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with hematite, tenorite, cassiterite, johillerite, nickenichite, calciojohillerite, bradaczekite, metathénardite, aphthitalite, langbeinite, calciolangbeinite, sanidine, fluorophlogopite, fluoborite, tilasite, anhydrite, pseudobrookite, sylvite, halite, lammerite, urusovite, ericlaxmanite, arsmirandite, svabite, krasheninnikovite, euchlorine, wulffite and alumoklyuchevskite. Badalovite forms oblique-angled prismatic crystals up to 1 mm × 1 mm × 5 mm, typically combined in groups or crusts up to several hundred cm2 in area. The mineral is transparent, green, grey, yellow or colourless, with vitreous lustre. It is brittle, the Mohs hardness is 3½. Cleavage was not observed, the fracture is uneven. Dcalc is 4.02 g cm–3. Badalovite is optically biaxial (–), α = 1.753(3), β = 1.757(3), γ = 1.758(3) and 2Vmeas. = 50(10)°. Chemical composition (wt.%, electron-microprobe; holotype) is: Na2O 9.23, K2O 0.19, CaO 2.04, MgO 13.78, MnO 0.31, CuO 0.12, ZnO 0.24, Al2O3 0.06, Fe2O3 12.77, TiO2 0.01, SiO2 0.06, P2O5 0.33, V2O5 0.05, As2O5 61.51, SO3 0.02, total 100.72. The empirical formula based on 12 O apfu is Na1.67Ca0.20K0.02Mg1.92Zn0.02Mn0.02Cu0.01Fe3+0.90Al0.01(As3.01P0.03Si0.01)Σ3.05O12. The simplified formula is Na2Mg2Fe3+(AsO4)3. Badalovite is monoclinic, C2/c, a = 11.9034(3), b = 12.7832(2), c = 6.66340(16) Å, β = 112.523(3)°, V = 936.59(4) Å3 and Z = 4. The strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 6.41(38)(020), 5.505(20)(200), 3.577(23)($\bar{1}$31), 3.523(25)(310), 3.211(46)($\bar{1}$12), 2.911(28)($\bar{2}$22, $\bar{3}$12), 2.765(100)(240, 400) and 2.618(26)($\bar{1}$32). The crystal structure was solved from single-crystal XRD data with an R1 of = 2.49%. Badalovite is isostructural with other alluaudite-group minerals. Its simplified crystal chemical formula is A(1)NaA(1)’□A(2) □A(2)’NaM(1)MgM(2)(Mg0.5Fe3+0.5)2(AsO4)3 (□ – vacancy) and the end-member formula is NaNaMg(MgFe3+)(AsO4)3. The mineral is named in honour of the outstanding mineralogist and geochemist Stepan Tigranovich Badalov (1919–2014).

The new mineral pansnerite, ideally K3Na3Fe3+6(AsO4)8, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with aphthitalite, hematite, sanidine, badalovite, khrenovite, achyrophanite, arsenatrotitanite, ozerovaite, tilasite, calciojohillerite, johillerite, nickenichite, svabite, katiarsite, yurmarinite, anhydrite, rutile, cassiterite and pseudobrookite. Pansnerite forms tabular to lamellar (flattened on {010}), usually pseudo-hexagonal crystals up to 0.2 mm × 0.7 mm × 1 mm and crystal clusters up to 2 mm across. It is transparent to translucent, light green, pale greenish, yellowish–greenish or yellowish, with vitreous lustre. The mineral is brittle, with perfect {010} cleavage. The Mohs’ hardness is ca 3. Dcalc is 3.596 g cm–3. Pansnerite is optically biaxial (–), α = 1.702(4), β = 1.713(4), γ = 1.717(4), 2Vmeas = 45(10)° and 2Vcalc = 62°. Chemical composition (holotype, wt.%, electron microprobe data) is: Na2O 6.39, K2O 8.52, CaO 0.08, MgO 0.08, MnO 0.02, NiO 0.02, CuO 1.35, ZnO 0.34, Al2O3 7.35, Cr2O3 0.04, Fe2O3 16.72, SiO2 0.16, P2O5 0.22, V2O5 0.09, As2O5 57.76, SO3 0.04, total 99.20. The empirical formula based on 32 O apfu is K2.86Na3.26Ca0.02(Fe3+3.31Al2.28Cu0.27Zn0.07Mg0.03Cr0.01)Σ5.97(As7.95P0.05Si0.04V0.02S0.01)Σ8.06O32. Pansnerite is orthorhombic, Cmce, a = 10.7372(3), b = 20.8367(8), c = 6.47335(15) Å, V = 1448.27(7) Å3 and Z = 2. The strongest reflections of the X-ray powder diffraction pattern [d,Å(I)(hkl)] are: 10.49(100)(020), 5.380(88)(111), 4.793(65)(220), 3.105(46)(311, 002), 3.079(32)(112, 061), 2.932(35)(260), 2.783(65)(202) and 2.694(52)(400, 222). The crystal structure was solved from single-crystal X-ray diffraction data, R1 = 2.82%. The structure is based on heteropolyhedral layers formed by MO6 octahedra (M = Fe3+ and Al) sharing common vertices and connected by AsO4 tetrahedra. Na+ and K+ cations are located in the interlayer space. The mineral is named in honour of the German–Russian mineralogist and geographer Lavrentiy Ivanovich Pansner (1777–1851). Pansnerite forms a solid-solution series with the isotypic mineral ozerovaite, ideally KNa2Al3(AsO4)4.

The new mineral zubkovaite, Ca3Cu3(AsO4)4, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with anhydrite, svabite, hematite, johillerite, tilasite, fluorophlogopite, sanidine and aphthitalite. Zubkovaite occurs as coarse prismatic crystals up to 0.01 mm × 0.01 mm × 0.2 mm combined in radiating aggregates or crusts. The mineral is transparent, bright sky-blue, turquoise-coloured or light bluish-green, with vitreous lustre. It is brittle, with imperfect cleavage. The Mohs’ hardness is ca 3. Dcalc is 4.161 g cm–3. Zubkovaite is optically biaxial (–), α = 1.747(5), β = 1.774(5), γ = 1.792(5) and 2Vmeas = 75(10)°. Chemical composition (wt.%, electron microprobe) is: CaO 19.22, CuO 27.37, As2O5 52.54, SO3 0.67, total 99.80. The empirical formula based on 16 O apfu is Ca2.96Cu2.97(As3.945S0.07)Σ4.015O16. Zubkovaite is monoclinic, C2, a = 16.836(3), b = 5.0405(8), c = 9.1173(17) Å, β = 117.388(13)°, V = 687.0(2) Å3 and Z = 2. The strongest reflections of the powder XRD pattern [d,Å (I) (hkl)] are: 7.44 (100) ($\bar 2$01), 3.727 (79) (400, $\bar 2$02, $\bar 3$11), 3.334 (92) ($\bar 1$12), 2.914 (73) (311), 2.765 (50) ($\bar 6$01, $\bar 6$02), 2.591 (96) ($\bar 3$13) and 2.521 (53) (020). The crystal structure is unique for minerals. It was solved from single-crystal X-ray diffraction data to R = 7.19%. The structure contains trimers of Cu2+-centred polyhedra (consisting of one distorted square CuO4 in the core and two distorted square pyramids CuO5) and two crystallographically independent As5+O4 tetrahedra playing different roles: As(2)O4 tetrahedra link neighbouring trimers into ribbons whereas As(1)O4 tetrahedra link adjacent ribbons into heteropolyhedral layers; Ca cations are located in the interlayer space. The mineral is named in honour of the Russian crystallographer and crystal chemist Natalia Vital'evna Zubkova (born 1976).

The new mineral antofagastaite, ideally Na2Ca(SO4)2·1.5H2O, was found in the oxidation zone of sulfide–quartz veins at the abandoned Coronel Manuel Rodríguez mine, Mejillones, Antofagasta Province, Antofagasta Region, Chile. It is associated with sideronatrite, metasideronatrite, aubertite, gypsum, ferrinatrite, glauberite, amarillite and an unidentified Fe phosphate. Antofagastaite occurs as prismatic crystals up to 0.5 mm × 1 mm × 5 mm, elongated along [010], typically combined in open-work aggregates up to 1 cm across. Antofagastaite is transparent and colourless, with vitreous lustre. It is brittle; the Mohs’ hardness is ca 3. Cleavage is distinct on (001). Dmeas. is 2.42(1) and Dcalc. is 2.465 g cm−3. Antofagastaite is optically biaxial (–), α = 1.489(2), β = 1.508(2), γ = 1.510(2) and 2Vmeas. = 40(10)°. The IR spectrum is reported. Chemical composition (wt.%, electron microprobe, H2O determined by gas chromatography) is: Na2O 20.85, CaO 17.42, SO3 52.56, H2O 7.93, total 98.76. The empirical formula (based on 8 O atoms belonging to sulfate anions per formula unit with all H belonging to H2O molecules) is Na2.06Ca0.95S2.01O8·1.35H2O. Antofagastaite is monoclinic, P21/m, a = 6.4596(4), b = 6.8703(5), c = 9.4685(7) Å, β = 104.580(4)°, V = 406.67(5) Å3 and Z = 2. The strongest reflections of the powder XRD pattern [d, Å (I, %) (hkl)] are: 9.17 (100) (001), 5.501 (57) (011), 3.437 (59) (020), 3.058 (43) (003), 2.918 (50) (2¯11), 2.795 (35) (013) and 2.753 (50) (121, 201). The crystal structure was solved based on single-crystal X-ray diffraction data, R1 = 5.71%. The structure of antofagastaite consists of ordered and disordered blocks and is related to syngenite K2Ca(SO4)2·H2O. Incorporation of additional H2O molecules in the syngenite-type structure results in disorder of the one of the two tetrahedral sulfate groups occurring in antofagastaite. In addition to the above-reported type material, antofagastaite together with syngenite and blödite occurs in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia.

The new mineral anatolyite Na6(Ca,Na)(Mg,Fe3+)3Al(AsO4)6 was found in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. It is associated with potassic feldspar, hematite, tenorite, cassiterite, johillerite, tilasite, ericlaxmanite, lammerite, arsmirandite, sylvite, halite, aphthitalite, langbeinite, anhydrite, wulffite, krasheninnikovite, fluoborite, pseudobrookite and fluorophlogopite. Anatolyite occurs as aggregates (up to 2 mm across) of rhombohedral–prismatic, equant or slightly elongated along [001] crystals up to 0.2 mm. The mineral is transparent, pale brownish–pinkish, with vitreous lustre. It is brittle, cleavage was not observed and the fracture is uneven. The Mohs’ hardness is ca 4½. Dcalc is 3.872 g cm–3. Anatolyite is optically uniaxial (–), ω = 1.703(4) and ε = 1.675(3). Chemical composition (wt.%, electron microprobe) is: Na2O 16.55, K2O 0.43, CaO 2.49, MgO 5.80, MnO 0.16, CuO 0.69, ZnO 0.55, Al2O3 5.01, Fe2O3 7.94, TiO2 0.18, SnO2 0.17, SiO2 0.04, P2O5 0.55, As2O5 60.75, SO3 0.03, total 101.34. The empirical formula based on 24 O apfu is (Na5.90K0.10)Σ6.00(Ca0.50Na0.13Zn0.08Mn0.03)Σ0.74(Mg1.63Fe3+1.12Al0.15Cu0.10)Σ3.00(Al0.96Ti0.03Sn0.01)Σ1.00(As5.97P0.09Si0.01)Σ6.07O24. Anatolyite is trigonal, R$\bar{3}$c, a = 13.6574(10), c = 18.2349(17) Å, V = 2945.6(4) Å3 and Z = 6. The strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 7.21(33)(012), 4.539(16)(113), 4.347(27)(211), 3.421(20)(220), 3.196(31)(214), 2.981(17)(223), 2.827(100)(125) and 2.589(18)(410). The crystal structure was solved from single-crystal XRD data to R = 4.77%. The structure is based on a 3D heteropolyhedral framework formed by M4O18 clusters [M1 = Al and M2 = (Mg,Fe3+)] linked with AsO4 tetrahedra. (Ca,Na) and Na cations centre A1O6 and A2O8 polyhedra in voids of the framework. Anatolyite is isostructural with yurmarinite. The new mineral is named in honour of the outstanding Russian crystallographer, mineralogist and mathematician Anatoly Kapitonovich Boldyrev (1883–1946).

A new tsumcorite-group mineral, nickeltsumcorite, Pb(Ni,Fe3+)2(AsO4)2(H2O,OH)2, the Ni-dominant analogue of tsumcorite and cobalttsumcorite, was found in the oxidation zone of a hydrothermal orebody containing gersdorffite and galena at the Km-3 mine, Lavrion, Attikí Prefecture, Greece. It is associated with annabergite, nickellotharmeyerite, nickelaustinite, gaspéite, calcite, dolomite, aragonite, quartz, goethite, cerussite, arseniosiderite, mimetite, oxyplumboroméite and Mn oxides/hydroxides. Nickeltsumcorite occurs as open-work aggregates and interrupted crusts up to 3 mm × 5 mm in area and up to 0.2 mm thick. They typically consist of coarse radial spherulites or dense concentric nodules up to 0.15 mm in diameter. Bunches or hemispherical clusters of crude individuals and separate imperfect, elongated crystals (up to 0.02 mm long) are also observed. Nickeltsumcorite is yellow, brownish-yellow, light brown or brown, with a yellow streak and a vitreous lustre. The Mohs hardness is ∼4. The mineral is brittle; one direction of distinct cleavage is observed under the microscope. D(calc.) = 5.02 g cm–3. Nickeltsumcorite is optically biaxial (–), α = 1.82(2), β = 1.87(1), γ = 1.90(1), 2V(obs.) is large. The chemical composition (wt.%, electron-microprobe data, H2O by difference) is CaO 2.79, PbO 28.12, MgO 0.30, CoO 0.15, NiO 17.39, ZnO 0.76, Mn2O3 0.57, Fe2O3 6.83, As2O5 38.17, H2O 4.92, total 100.00. The empirical formula, calculated based on 10 O apfu, is (Pb0.76Ca0.30)∑1.06(Ni1.39Fe3+0.51Zn0.06Mn3+0.04 Mg0.04Co0.01)∑2.05As1.99O7.97[(H2O)1.25(OH)0.78]. The strongest reflections in the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 4.64 (100) (1̄11), 4.47 (41)(2̄01), 3.238 (82)(1̄12), 3.008(60)(201), 2.859(41)(021), 2.545(79)(3̄12, 112), 2.545 (79)(3̄12, 112) and 2.505 (61)(220, 2̄03). The cation composition, powder Xray diffraction data and IR spectrum show that nickeltsumcorite belongs to the tsumcorite structure type. The new mineral is monoclinic, space group C2/m, a = 9.124(8), b = 6.339(3), c = 7.567(7) Å, β = 115.19(6)°, V = 396.0(7) Å3 and Z = 2. Nickeltsumcorite forms a solid-solution series with nickellotharmeyerite.