Atali A. Agakhanov

Manganoblödite, Na2Mn(SO4)2·4H2O, and cobaltoblödite, Na2Co(SO4)2·4H2O: two new members of the blödite group from the Blue Lizard mine, San Juan County, Utah, USA

Abstract Two new minerals - manganoblödite (IMA2012-029), ideally Na2Mn(SO4)2·4H2O, and cobaltoblödite (IMA2012-059), ideally Na2Co(SO4)2·4H2O, the Mn-dominant and Co-dominant analogues of blödite, respectively, were found at the Blue Lizard mine, San Juan County, Utah, USA. They are closely associated with blödite (Mn-Co-Ni-bearing), chalcanthite, gypsum, sideronatrite, johannite, quartz and feldspar. Both new minerals occur as aggregates of anhedral grains up to 60 μm (manganoblödite) and 200 μm (cobaltoblödite) forming thin crusts covering areas up to 2 × 2 cm on the surface of other sulfates. Both new species often occur as intimate intergrowths with each other and also with Mn-Co-Ni-bearing blödite. Manganoblödite and cobaltoblödite are transparent, colourless in single grains and reddish-pink in aggregates and crusts, with a white streak and vitreous lustre. Their Mohs‘ hardness is ~2½. They are brittle, have uneven fracture and no obvious parting or cleavage. The measured and calculated densities are Dmeas = 2.25(2) g cm−3 and Dcalc = 2.338 g cm−3 for manganoblödite and Dmeas = 2.29(2) g cm−3 and Dcalc = 2.347 g cm−3 for cobaltoblödite. Optically both species are biaxial negative. The mean refractive indices are α = 1.493(2), β = 1.498(2) and γ = 1.501(2) for manganoblödite and α = 1.498(2), β = 1.503(2) and γ = 1.505(2) for cobaltoblödite. The chemical composition of manganoblödite (wt.%, electron-microprobe data) is: Na2O 16.94, MgO 3.29, MnO 8.80, CoO 2.96, NiO 1.34, SO3 45.39, H2O (calc.) 20.14, total 98.86. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na1.96(Mn0.44Mg0.29Co0.14Ni0.06)Σ0.93S2.03O8·4H2O. The chemical composition of cobaltoblödite (wt.%, electron-microprobe data) is: Na2O 17.00, MgO 3.42, MnO 3.38, CoO 7.52, NiO 2.53, SO3 45.41, H2O (calc.) 20.20, total 99.46. The empirical formula, calculated on the basis of 12 O a.p.f.u., is: Na1.96(Co0.36Mg0.30Mn0.17Ni0.12)Σ 0.95S2.02O8·4H2O. Both minerals are monoclinic, space group P21/a, with a = 11.137(2), b = 8.279(1), c = 5.5381(9) Å, β = 100.42(1)°, V = 502.20(14) Å3 and Z = 2 (manganoblödite); and a = 11.147(1), b = 8.268(1), C = 5.5396(7) Å, β = 100.517(11)°, V = 501.97(10) Å3 and Z = 2 (cobaltoblödite). The strongest diffractions from X-ray powder pattern [listed as (d,Å(I)(hkl)] are for manganoblödite: 4.556(70)(210, 011); 4.266(45)(2̅01); 3.791(26)(2̅11); 3.338(21)(310); 3.291(100)(220, 021), 3.256(67)(211,1̅21), 2.968(22)(2̅21), 2.647(24)(4̅01); for cobaltoblödite: 4.551(80)(210, 011); 4.269(50)(2̅01); 3.795(18)(2̅11); 3.339(43)(310); 3.29(100)(220, 021), 3.258(58)(211, 1̅21), 2.644(21)( 4̅01), 2.296(22)( 1̅22). The crystal structures of both minerals were refined by single-crystal X-ray diffraction to R1 = 0.0459 (manganoblödite) and R1 = 0.0339 (cobaltoblödite).

The crystal structure and crystal chemistry of mendeleevite-(Ce), (Cs,□)6(□,Cs)6(□,K)6(REE,Ca,□)30(Si70O175)(H2O,OH,F,□)35, a potential microporous material

Abstract The crystal structure of mendeleevite-(Ce), (Cs,⃞)6(⃞,Cs)6(⃞,K)6(REE,Ca,⃞)30(Si70O175) (H2O,OH,F,⃞)35, a new mineral from the moraine of the Darai-Pioz glacier, the Alai mountain ridge, Tien-Shan mountains, northern Tajikistan, was solved by direct methods and refined to R1 = 4.15% based on 2274 observed [Fo > 4σ|F|] unique reflections measured with Mo-Kα radiation on a Bruker P4 diffractometer equipped with a CCD detector. Mendeleevite-(Ce) is cubic, space group Pm3̄, a 21.9148(4) Å, V 10525(1) Å3, Z = 2, Dcalc = 3.066 g/cm3. The empirical formula (electron microprobe) is Cs5.94K2 .22[(Ce11.35La5.86Nd3.23Pr1.54Sm0.32Gd0.20)∑22.50(Ca4.68Sr1.00)∑5.68]∑28.18 Si70.12O203.17H45.67F6.83, Z = 2, calculated on the basis of 210 (O + F) a.p.f.u., with H2O and OH calculated from structure refinement (OH + F = 17 p.f.u.; H2O = 17.75 p.f.u.). The structural formula is (Cs4.65⃞1.35)∑6(⃞4.71Cs1.29)∑6(⃞3.78K2.22)∑6{[(Ce11.35La5.86Nd3.23 Pr1.54Sm0.32Gd0.20)∑22.50(Ca4.68Sr1.00)∑5.68]∑28.18⃞1.82}∑30(Si70O175)[(OH)10.17F6.83]∑17(H2O)17.75. Simplified and endmember formulae are as follows: (Cs,⃞)6(⃞,Cs)6(⃞,K)6(REE,Ca,⃞)30(Si70O175)(H2O,OH,F,⃞)35 and Cs6(REE22Ca6)(Si70O175)(OH,F)14(H2O)21. The crystal structure of mendeleevite-(Ce) is an intercalation of two independent Si-O radicals and an M framework of (REE,Ca) polyhedra. The Si-O radicals are an(Si 104O260)104- framework and an (Si36O90)36-cluster which do not link directly. The M framework is located between the Si-O framework and the Si-O clusters. Interstitial cations occupy two types of cages and channels. Cages I and II are 78 and 22% occupied by Cs. Channels along [100⃞] contain K atoms and H2O groups. Mendeleevite-(Ce) has no natural or synthetic structural analogues. Mendeleevite-(Ce) is a framework mineral with large cavities and it has the potential to be used as a model for the synthesis of microporous materials of industrial interest.

Thallium-rich murunskite from the Lovozero pluton, Kola Peninsula, and partitioning of alkali metals and thallium between sulfide minerals

A new thallium-rich variety of murunskite has been found in the Palitra peralkaline pegmatite at Mount Kedykverpakhk, the Lovozero alkaline pluton, Kola Peninsula, Russia. This mineral occurs as a flattened dark bronze segregation (0.3 × 0.8 × 0.8 mm) overgrowing ussingite in a cavity. The chemical composition is as follows, wt %: 8.35 K, 24.31 Tl, 29.01 Cu, 14.58 Fe, 23.26 S, total is 99.51. The empirical formula is (K1.18Tl0.66)1.84(Cu2.53Fe1.45)3.98S4.02. According to X-ray powder diffraction data, the dimensions of the tetragonal unit cell are: a = 3.869 (1), c = 13.206 (6) Å, V = 197.7 (2) Å3. This variety is the closest to the intermediate member of the murunskite-thalcusite series. The youngest mineral complex of the Palitra Pegmatite includes four sulfides belonging to three different structure types. These sulfides also may be regarded as three topological types distinguished by the arrangement of alkali metal atoms in their structures: (1) bartonite and chlorbartonite belonging to the zero-dimensional topological type with K atoms in isolated cells, (2) pautovite pertaining to the one-dimensional type with Cs (+Rb, K, Tl) atoms making up chains in ample tunnels, and (3) murunskite belonging to the two-dimensional type with K (+Tl) atoms forming sheets. There is pronounced partitioning of K (Cs + Rb) and Tl between these sulfides: bartonite and chlorbartonite contain 9.5–9.7 wt % K and 0.2 wt % Tl; pautovite, 36.1 wt % Cs, 1.3 wt % Rb, 0.5 wt % Tl, and 0.2 wt % K; and murunskite, 8.35 wt % K and 24.31 wt % Tl.

Byzantievite, Ba5(Ca,REE,Y)22(Ti,Nb)18(SiO4)4[(PO4),(SiO4)]4 (BO3)9O21[(OH),F]43(H2O)1.5: the crystal structure and crystal chemistry of the only known mineral with the oxyanions (BO3), (SiO4) and (PO4)

Abstract The crystal structure of byzantievite, Ba5(Ca,REE,Y)22(Ti,Nb)18(SiO4)4[(PO4),(SiO4)]4(BO3)9O21 [(OH),F]43(H2O)1.5, a new mineral from the moraine of the Dara-i-Pioz glacier, the Alai mountain ridge, Tien-Shan Mountains, northern Tajikistan, was solved by direct methods and refined to R1 = 13.14% based on 3794 observed [Fo >4σ|F|] unique reflections measured with Mo-Ka X-radiation on a Bruker P4 diffractometer equipped with a CCD detector. Byzantievite is hexagonal, space group R3, a = 9.1202(2) Å, c = 102.145(5) Å, V = 7358.0(5) Å3, Z = 3, Dcalc. = 4.151 g cm−3. The empirical formula (electron microprobe analysis) is Ba5.05[(Ca8.99Sr0.96Fe2+0.42Na0.20)∑10.5(Ce3.46La1.54Nd1.20 Pr0.30Sm0.26Dy0.41Gd0.32Th0.39U4+0.17)∑8.05Y3.53]∑22.15(Ti12.31Nb5.30)∑17.61(SiO4)4.65(PO4)3.12(BO3)8.89 O22.16(OH)38.21F4.89(H2O)1.5, Z = 3, calculated on the basis of 124.5 (O + F) a.p.f.u. The H2O and OH contents were calculated from structure refinement (F + OH = 43 a.p.f.u.; H2O = 1.5 a.p.f.u..), and B was determined by SIMS. The crystal structure is a framework of Ti-Ba-Ca-REE-dominant polyhedra and SiO4, PO4 and BO3 groups. In the crystal structure, there are 50 cation sites, 23 of which are fully occupied and 27 partly occupied: six of the 27 partly-occupied sites are >50% occupied, 21 <50% occupied. The crystal structure of byzantievite is an intercalation of three components, one fully ordered with 100% occupancy of cation sites, and two partly ordered with cation-site occupancies of 67% and 17% respectively. Byzantievite is the only known mineral that contains all three of the oxyanions (BO3), (SiO4) and (PO4) as essential components.

Yusupovite, Na2Zr(Si6O15)(H2O)3, a new mineral species from the Darai-Pioz alkaline massif and its implications as a new microporous filter for large ions

Abstract Yusupovite, ideally Na2Zr(Si6O15)(H2O)3, is a new silicate mineral from the Darai-Pioz alkaline massif in the upper reaches of the Darai-Pioz river, area of the joint Turkestansky, Zeravshansky, and Alaisky ridges, Tajikistan. Yusupovite was found in a pegmatite composed mainly of reedmergnerite, aegirine, microcline, and polylithionite. It occurs as prismatic grains about 2 mm in size embedded in reedmergnerite; associated minerals are quartz, pectolite, zeravshanite, mendeleevite-(Ce), fluorite, leucosphenite, a pyrochlore-group mineral, neptunite, telyushenkoite, moskvinite-(Y), and shibkovite. Yusupovite is colorless, transparent with a white streak, has a vitreous luster, and does not fluoresce under ultraviolet light. Cleavage is perfect on {110}, parting was not observed. Mohs hardness is 5. Yusupovite is brittle with a splintery fracture. The measured and calculated densities are 2.69(2) and 2.713 g/cm3, respectively. Yusupovite is optically biaxial (+) with refractive indices (λ = 589 nm) α = 1.563(2), β = 1.565(2), γ = 1.577(2); 2Vmeas = 42(3)°, 2Vcalc = 45°, strong dispersion: r > v. Yusupovite is monoclinic, C2/m, a = 14.5975(4), b = 14.1100(4), c = 14.4394(4) Å, β = 90.0399(4)°, V = 2974.1(3) Å3. The six strongest reflections in the X‑ray powder diffraction data [d (Å), I, (hkl)] are 7.05, 100, (020); 3.24, 96, (420); 3.10, 69, (241, 2̅41); 5.13, 53, (202, 2̅02); 6.51, 42, (201, 2̅01); 3.17, 34, (042). The chemical composition (electron microprobe) is: Nb2O5 0.39, SiO2 58.84, ZrO2 16.55, HfO2 0.30, FeO 0.01, Y2O3 3.05, Cs2O 2.58, K2O 0.95, Na2O 8.91, H2Ocalc 7.40, total 98.98 wt%, with H2O calculated from structure refinement. The empirical formula (based on 17.5 O apfu) is (Na1.76K0.12Cs0.11)∑1.99 (Zr0.82Y0.17Nb0.02Hf0.01)∑1.02(Si6.01O14.98)(H2O)2.52, Z = 8. The crystal structure of yusupovite was refined to R1 = 3.46% based on 4428 observed reflections. In the crystal structure, there are six Si sites occupied by Si, two M sites occupied mainly by Zr with minor Y and Hf. Si tetrahedra form an epididymite Si6O15 ribbon along [010]. Epididymite ribbons and Zr-dominant M octahedra share common vertices to form a heteropolyhedral Si-Zr-O framework. There are six interstitial sites partly occupied by alkali cations Na, K, and Cs. The three [7]-coordinated Na sites are occupied by Na at 95, 84, and 78%. The three A sites are occupied by K and Cs at 12, 18, and 16%. There are 10 W sites occupied by H2O groups at 18-84%. Due to (K,Cs), Na and H2O disorder, the symmetry of yusupovite decreases from orthorhombic, space group Pbcm (elpidite), to monoclinic, space group C2/m, and the b unit-cell parameter of yusupovite is doubled compared to the corresponding cell parameter in elpidite, byus = 2aelp. Yusupovite, ideally Na2Zr(Si6O15)(H2O)3, is a dimorph of elpidite, Na2Zr(Si6O15)(H2O)3.

Nestolaite, CaSeO3·H2O, a new mineral from the Little Eva mine, Grand County, Utah, USA

Abstract Nestolaite (IMA 2013-074), CaSeO3·H2O, is a new mineral species from the Little Eva mine, Grand County, Utah, USA. It is named in honour of the prominent Italian mineralogist and crystallographer Fabrizio Nestola. The new mineral was found on sandstone matrix as rounded aggregates up to 2 mm across and up to 0.05 mm thick consisting of tightly intergrown oblique-angled, flattened to acicular crystals up to 30 mm long and up to 7 mm (very rarely up to 15 mm) thick. Nestolaite associates with cobaltomenite, gypsum, metarossite, orschallite and rossite. The new mineral is light violet and transparent with a white streak and vitreous lustre. The Mohs hardness is 2½. Nestolaite is brittle, has uneven fracture and perfect cleavage on {100}. The measured and calculated densities are Dmeas. = 3.18(2) g/cm3 and Dcalc. = 3.163 g/cm3. Optically, nestolaite is biaxial positive. The refractive indices are α = 1.642(3), β = 1.656(3), γ = 1.722(6). The measured 2V is 55(5)° and the calculated 2V is 51°. In transmitted light nestolaite is colourless. It does not show pleochroism but has strong pseudoabsorption caused by high birefringence. The chemical composition of nestolaite (wt.%, electronmicroprobe data) is: CaO 28.97, SeO2 61.14, H2O (calc.) 9.75, total 99.86. The empirical formula calculated on the basis of 4 O a.p.f.u. (atoms per formula unit) is Ca0.96Se1.02O3·H2O. The Raman spectrum is dominated by the Se-O stretching and O-Se-O bending vibrations of the pyramidal SeO3 groups and O-H stretching modes of the H2O molecules. The mineral is monoclinic, space group P21/c, with a = 7.6502(9), b = 6.7473(10), c = 7.9358(13) Å , β = 108.542 (12)°, V = 388.37(10) Å3 and Z = 4. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) (Irel)]: 7.277 (100)(100), 4.949 (110)(37), 3.767 (002)(29), 3.630 (200)(58), 3.371 (020)(24), 3.163 (2̄02)(74), 2.9783 (1̄21)(74) and 2.7231 (112)(31). The crystal structure of nestolaite was determined by means of the Rietveld refinement from the powder data to Rwp = 0.019. Nestolaite possesses a layered structure consisting of CaΦ-SeO3 sheets, composed of edge-sharing polyhedra. Adjacent sheets are held by H bonds emanating from the single (H2O) group within the sheets. The nestolaite structure is topologically unique.

The crystal structure of laptevite-(Ce), NaFe2+(REE7Ca5Y3)(SiO4)4(Si3B2PO18)(BO3)F11, a new mineral species from the Darai-Pioz alkaline massif, Northern Tajikistan

Abstract Laptevite-(Ce), ideally NaFe2+(REE7Ca5Y3) · (SiO4)4(Si3B2PO18)(BO3)F11, is a new member of the vicanite group discovered in the moraine of the Darai-Pioz glacier, Alai Mountain Range, Tien-Shan, Tajikistan. The crystal structure of laptevite-(Ce), trigonal, a = 10.804(2) Å , c = 27.726(6) Å , V = 2802.6(2) Å 3, sp. gr. R3m, Z = 3, Dcalc. = 4.660 · 103 kg/m3, has been refined to R1 = 0.0387 for 924 unique (Fo > 4σF) reflections, collected on a Bruker single-crystal P4 diffractometer with a 4K CCD detector and Mo-Ka X-radiation. The simplified formula is NaFe2+(REE,Ca,Y)15(SiO4)4 [(Si,B,P)6O18](BO3)F11. In the crystal structure of laptevite-( Ce), there are four tetrahedrally coordinated T sites. The T(1) site is occupied by Si and minor B, 〈T(1)-O〉 = 1.594 Å ; the T(2, 3) sites are occupied by Si, 〈T(2,3)-O〉 = 1.64 Å ; the T(4) site is occupied by B, P and minor Si, with 〈T(4)-O〉 = 1.51 Å . The [3]-coordinated T(5) site has composition B0.84⃞0.16, with 〈T(5)-O〉 = 1.42 Å . Cations at the T(1 + 4), T(2, 3) and T(5) sites form the complex anions (Si3B2PO18), (SiO4)4 and (BO3), respectively. The [7-10-coordinated M(1-5) sites are occupied by REE, Ca, Y and minor Sr, with 〈M(1-5)-O〉 = 2.37-2.62 Å . The octahedrally coordinated M(6) site is occupied by Fe2+ > Mn > Ti, with 〈M(6)-O〉 =2.13 Å . The [10]-coordinated M(7) site has composition Na0.75REE0.25, with 〈M(7)-O〉 = 2.64 Å . The T and M polyhedra form a framework. Laptevite-(Ce) is isostructural with other vicanite-group minerals: vicanite- (Ce), okanoganite-(Y), hundholmenite-(Y) and proshchenkoite-(Y). Vicanite-group structures differ in the dominant cation species at the T(1, 3-6) and M(3-7) sites.

Chemistry of Cancrinite-Group Minerals from the Khibiny-Lovozero Alkaline Complex, Kola Peninsula, Russia

Natural and synthetic microporous compounds of hexagonal symmetry with the general formula A 6−8[T I T IIO4]6 X 1−4 · nH2O (A = Na +, K +, Ca 2+; T I= Al 3+; T II= Si 4+, Ge4+; X= Cl −, (OH) −, (NO3)−, (CO 3) 2−, (SO 4) 2−, S 2−, (MoO4)2−, (WO4)2−, (PO4)3−, (VO4)3−; species-forming constituents of minerals are marked boldtype) form the cancrinite family. The cancrinite-type structures are characterized by a framework of T I T IIO4 tetrahedra. The alternating AlO4 and SiO4 tetrahedra form six-membered rings. Within a framework, wide continuous channels parallel to the 63 axis and chains of small cages (cancrinite cages) along the three-fold axes occur. This structural cavities host alkaline and alkaline-earth cations (A), and a wide variety of extra-framework anions, as well as H2O molecules (Bonaccorsi and Merlino, 2005).

Mendeleevite-(Nd), (Cs,□)6(□,Cs)6(□,K)6(REE,Ca)30(Si70O175)(OH,H2O,F)35, a new mineral from the Darai-Pioz alkaline massif, Tajikistan

Abstract Mendeleevite-(Nd), (Cs,□)6(□,Cs)6(□,K)6(REE,Ca)30(Si70O175)(OH,H2O,F)35 is a new mineral from the Darai-Pioz alkaline massif, Tajikistan. Mendeleevite-(Nd) was found in a pectolite aggregate in silexites (quartz-rich rocks) which consist of fine to medium pectolite grains, quartz, aegirine and fluorite, with minor khvorovite, mendeleevite-(Ce), sokolovaite, hyalotekite, orlovite, kirchhoffite, pekovite, neptunite, zeravshanite, senkevichite, nordite-(Се), alamosite, pyrochlore-group minerals and baratovite. Mendeleevite-(Nd) forms colourless cubic crystals 10-40 μm in size; it has a vitreous lustre and a Mohs hardness of 5-5.5; Dmeas. = 3.20(2) g/cm3, Dcalc. = 3.155 g/cm3. Mendeleevite-(Nd) is optically isotropic, with the refractive index n = 1.582(2). Mendeleevite-(Nd) is cubic, space group Pm3̅, a = 21.9106(4) Å; Z = 2. The six strongest reflections in the powder X-ray diffraction pattern are [d (Å), I (%), (h k l)] are: 11.01, 100, (0 0 2); 15.63, 55, (0 1 1); 3.47, 42, (2 0 6); 3.099, 42, (3 4 5); 2.192, 42, (0 0 10); 1.819, 41, (3 6 10). Chemical analysis by electron microprobe gave SiO2 42.30, Ce2O3 10.12, La2O3 3.60, Nd2O3 16.19, Pr2O3 2.79, Sm2O3 4.19, Gd2O3 1.69, Eu2O3 0.47, SrO 2.99, CaO 2.20, Cs2O 8.50, K2O 0.85, H2O 3.85, F 1.25, -O = F2 -0.53, sum 100.46 wt.%, with H2O calculated by analogy with mendeleevite-(Ce). The empirical formula based on 210 (O + F) apfu, with F + OH + H2O = 35 pfu, is Cs6(□4.20K1.80)Σ6{[(Nd9.57Ce6.13Sm2.39La2.20Pr1.68Gd0.93Eu0.27)Σ23.17(Ca3.90Sr2.87)Σ6.77]Σ29.94□0.06}Σ30(Si70.03O175)(OH14.47F6.54)Σ21.01(H2O)14, Z = 2. The simplified and ideal formulae are (Cs,□)6(□,Cs)6(□,K)6(REE,Ca)30(Si70O175)(OH, H2O,F)35 and Cs6(REE23Ca7)(Si70O175)(OH,F)19(H2O)16, respectively. The compatibility index (from measured density) = -0.039 (excellent). Mendeleevite-(Nd) is a Nd analogue of mendeleevite-(Ce), (Cs,□)6(□,Cs)6(□,K)6(REE,Ca,□)30(Si70O175)(H2O,OH,F,□)35. Both minerals are named after Dmitri Mendeleev (1834-1907), the great Russian chemist, author of the periodic table of chemical elements, who has had a significant impact on the development of natural sciences and industry, both in Russia and around the world.

Refinement of the crystal structure of berezanskite, Ti2□2KLi3(Si12O30)

Abstract Berezanskite, ideally Ti2□2KLi3(Si12O30), is hexagonal, space group P6/mcc, a = 9.898(4), c = 14.276(6) Å, V = 1211.2(9) Å3, Z = 2. The crystal structure was refined to an R1 index of 2.08% based on 392 unique observed reflections. Berezanskite is isostructural with milarite, ideally ACa2BoCKT(2)(Be2Al)(T(1)Si12O30)(H2O)0-2. The structural unit is of the form[T(2)3T(1)12O30]with T(1) = Si and T(2) = Li, inwhich (LiO4) tetrahedra link [Si12O30] six-membered double-rings into a framework. The A, B and C sites occur in the interstices of the framework with the following site populations: A=Ti4+2 , =1.938(2)Å; B =□2; C=K, = 3.058(2) Å. In the T(2) = Li3 milarite-group minerals, the distance is inversely related to the occupancy of the B site.