A new eudialyte-group mineral, ilyukhinite, ideally (H3O,Na)14Ca6Mn2Zr3Si26O72(OH)2 · 3H2O, has been found in peralkaline pegmatite at Mt. Kukisvumchorr, Khibiny alkaline pluton, Kola Peninsula, Russia. It occurs as brownish orange, with vitreous luster anhedral grains up to 1 mm across in hydrothermally altered peralkaline rock, in association with aegirine, murmanite, albite, microcline, rhabdophane-(Ce), fluorite, sphalerite and molybdenite. The Mohs hardness is 5; cleavage is not observed. Dmeas 2.67(2), Dcalc 2.703 g/cm3. Ilyukhinite is optically uniaxial (–): ω = 1.585(2), ε = 1.584(2). The IR spectrum is given. The average chemical composition of ilyukhinite (wt %; electron microprobe, ranges given in parentheses; H2O determined by gas chromatography) is as follows: 3.07 (3.63–4.43) Na2О, 0.32 (0.28–0.52) K2O, 10.63 (10.26–10.90) CaO, 3.06 (2.74–3.22) MnO, 1.15 (0.93–1.37) FeO, 0.79 (0.51–0.89) La2O3, 1.21 (0.97–1.44) Ce2O3, 0.41 (0.30–0.56) Nd2O3, 0.90 (0.77–1.12) TiO2, 10.94 (10.15–11.21) ZrO2, 1.40 (0.76–1.68) Nb2O5, 51.24 (49.98–52.28) SiO2, 1.14 (0.89–1.37) SO3, 0.27 (0.19—0.38) Cl, 10.9(5 )H2O,–0.06–O = C1, total is 98.27. The empirical formula is H36.04(Na3.82K0.20)(Ca5.65Ce0.22La0.14Nd0.07)(Mn1.285Fe0.48)(Zr2.645Ti0.34)Nb0.31Si25.41S0.42Cl0.23O86.82. The crystal structure has been solved (R = 0.046). Ilyukhinite is trigonal, R3m; a = 14.1695(6) Å, b = 31.026(1) Å, V = 5394.7(7) Å3, Z = 3. The strongest XRD reflections [d, Å (I, %) (hkl)] are 11.44 (82) (101), 7.09 (70) (110), 6.02 (44) (021), 4.371 (89) 205), 3.805 (47) (303, 033), 3.376 (41) (131), 2.985 (100) (315, 128), 2.852 (92) (404). Ilyukhinite was named in memory of Vladimir V. Ilyukhin (1934–1982), an outstanding Soviet crystallographer. The type specimen of ilyukhinite has been deposited in the collection of the Natural History Museum, University of Oslo, Norway.

The crystal structure of the hydrated analog of the mineral rastsvetaevite (tentatively called “hydrorastsvetaevite”), which was found by A.P. Khomyakov in ultraagpaitic pegmatites at the Rasvumchorr Mountain of the Khibiny alkaline massif (Kola Peninsula), has been determined by single crystal X-ray diffraction. The trigonal unit-cell parameters are as follows: a = 14.2812(2) Å, c = 60.533(5) Å, V = 10691.54(3) Å3, sp. gr. R3m. The structure was refined to R = 5.9% in the isotropic and anisotropic approximation of atomic displacement parameters based on 2068 ref lections with |F| > 3σ(F). “Hydrorastsvetaevite” is on the whole analogous to other 24-layer representatives of the eudialyte group (called “megaeudialytes”), but is characterized by a high potassium content and is distinguished from other potassium-rich minerals (rastsvetaevite, davinciite, and andrianovite) by low sodium and alkaline-earth metal content, as well as by a high degree of hydration accompanied by the insertion of H3O groups, which partially or completely replace large cations. The idealized formula of “hydrorastsvetaevite” (Z = 3) is (Na11(H3O)11K6(H2O)1.5Sr)Ca12Fe3Na2MnZr6Si52O144(OH)4.5Cl3.5(H2O)0.5. In alkaline pegmatites, “hydrorastsvetaevite” occurs as a secondary mineral developed from the original rastsvetaevite through decationation and hydration. The characteristic features of the genesis of eudialyte-group minerals containing potassium as a species-forming cation are discussed in terms of the concept of transformational mineral species.an]Mis||Original Russian Text © R.K. Rastsvetaeva, S.M. Aksenov, K.A. Rozenberg, 2015, published in Kristallografiya, 2015, Vol. 60, No. 6, pp. 897–905.

The structure of the sodium-rich representative of the eudialyte group found by A.P. Khomyakov at the Lovozero massif (Kola Peninsula) is studied by X-ray diffraction. The trigonal cell parameters are: a = 14.2032(1) and c = 60.612(1) Å, V = 10589.13 Å3, space group R3m. The structure is refined to the final R = 5.0% in the anisotropic approximation of atomic displacement parameters using 3742|F| > 3σ(F). The idealized formula (Z = 3) is Na37Ca10Mn2FeZr6Si50(Ti, Nb)2O144(OH)5Cl3 · H2O. Like other 24-layer minerals of the eudialyte group, this mineral has a modular structure. Its structure contains two modules, namely, “alluaivite” (with an admixture of “eudialyte”) and “kentbrooksite,” called according to the main structural fragments of alluaivite, eudialyte, and kentbrooksite. The mineral found at the Lovozero alkaline massif shows some chemical and symmetry-structural distinctions from the close-in-composition labyrinthite modular mineral from the Khibiny massif. The difference between the minerals stems from different geochemical conditions of mineral formation in the two regions.

The variations in the chemical composition of lamprophyllite-group minerals from a peralkaline dyke of the Mokhnatye Roga area (Kandalaksha region, Kola Peninsula), which are crystallized during the entire period of dyke formation and form several generations, have been investigated. The early generations differ in a steadily high fluorine content, while the later ones exhibit reduced amount of fluorine, impurity elements, and sodium, with a simultaneous increase in the potassium content. The crystal structure of fluorine- rich barytolamprophyllite (potentially a new representative of the lamprophyllite group, differing by the predominance of fluorine in the anion X site) has been analyzed by single crystal X-ray diffraction. This mineral is found to have a monoclinic unit cell with the following parameters: a = 19.5219(8) Å, b = 7.0915(2) Å, c = 5.3925(2) Å, β = 96.628(3)°, and sp. gr. C2/m. The structure is refined to R = 5.73% in the anisotropic approximation of the atomic displacement parameters using 3668I > 2σ(I). The idealized formula (Z = 2) is (Ba,Sr)2[Na(Na,Fe)2(Ti,Mg)F2][Ti2(Si2O7)2O2].

This paper presents a description of a new zirconosilicate of the eudialyte group, which was named davinciite in honor of Leonardo da Vinci (1452–1519), a famous Italian scientist, painter, sculptor and archi tect. The new mineral has been found in hyperagpaitic pegmatite at the Rasvumchorr Mountain, Khibiny Pluton, Kola Peninsula, as relict inclusions, up to 1–2 mm in size in a rastsvetaevite matrix. It is associated with nepheline, sodalite, potassium feldspar, delhayelite, aegirine, shcherbakovite, villiaumite, nitrite, nacaphite, rasvumite, and djerfisherite. Davinciite is dark lavender and transparent, with a vitreous luster and white streak. The new mineral is brittle, with conchoidal fracture; the Mohs’ hardness is 5. No indications of cleavage or parting were observed. The measured density is 2.82(2) g/cm3 (volumetric method); the calcu lated density is 2.848 g/cm3. Davinciite is optically uniaxial, positive; ω = 1.603(2), ε = 1.605(2). It is nonp leochroic and nonfluorescent in UV light. The new mineral slowly breaks down and gelates in 50% HCl and HNO3. It is trigonal, space group R3m. The unit cell dimensions are a = 14.2956(2), c = 30.0228(5) Å, V= 5313.6(2) Å3. The strongest reflections in the X ray powder diffraction pattern [d, Å (I, %) (hkl)] are as fol lows: 2.981(100)(315), 2.860(96)(404), 4.309(66)(205), 3.207(63)(208), 6.415(54)(104), 3.162(43)(217). The chemical composition (electron microprobe, H2O calculated from X ray diffraction data) is as follows, wt %: 12.69 Na2O, 3.53 K2O, 11.02 CaO, 0.98 SrO, 0.15 BaO, 5.33 FeO, 0.37 MnO, 0.07 Al2O3, 51.20 SiO2, 0.39 TiO2, 11.33 ZrO2, 0.21HfO2, 0.09 Nb2O5, 1.89 Cl, 0.93H2O, –O = Cl2 0.43; total is 99.75. The empirical formula calculated on the basis of Si + Al + Zr + Hf + Ti + Nb = 29 (Z = 3) is (Na1l.75Sr0.29Ba0.03)Σ12.07(K2.28Na0.72)Σ3Ca5.99(Fe2.26Mn0.16)Σ2.42(Zr2.80Ti0.15Hf0.03Nb0.02)Σ3(Si1.96Al0.04)Σ2[Si3O9]2 [Si9O27]2[(OH)1.42O0.58]Σ2[Cl1.62(H2O)0.38]Σ2 ⋅ 0.48H2O. The simplified formula is Na12K3Ca6 Zr3(Si26O73OH)Cl2. The IR spectrum is given and the crystal structure is described. The position of davinciite in the crystal chemical taxonomy of the eudialyte group is shown, and its relationships with the other eudialyte group minerals (acentric eudialyte, andrianovite, and kentbrooksite) are character ized. The type material of davinciite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow. DOI: 10.1134/S1075701513070076 Fe3 2+

This paper presents a description of a new zirconosilicate of the eudialyte group, which was named davinciite in honor of Leonardo da Vinci (1452–1519), a famous Italian scientist, painter, sculptor and architect. The new mineral has been found in hyperagpaitic pegmatite at the Rasvumchorr Mountain, Khibiny Pluton, Kola Peninsula, as relict inclusions, up to 1–2 mm in size in a rastsvetaevite matrix. It is associated with nepheline, sodalite, potassium feldspar, delhayelite, aegirine, shcherbakovite, villiaumite, nitrite, nacaphite, rasvumite, and djerfisherite. Davinciite is dark lavender and transparent, with a vitreous luster and white streak. The new mineral is brittle, with conchoidal fracture; the Mohs’ hardness is 5. No indications of cleavage or parting were observed. The measured density is 2.82(2) g/cm 3 (volumetric method); the calculated density is 2.848 g/cm 3 . Davinciite is optically uniaxial, positive; ω = 1.603(2), ɛ = 1.605(2). It is nonpleochroic and nonfluorescent in UV light. The new mineral slowly breaks down and gelates in 50% HCl and HNO 3 . It is trigonal, space group R3m . The unit-cell dimensions are a = 14.2956(2), c = 30.0228(5) Å, V =5313.6(2) Å 3 . The strongest reflections in the X-ray powder diffraction pattern [ d , Å ( I , %) ( hkl )] are as follows: 2.981(100)(315), 2.860(96)(404), 4.309(66)(205), 3.207(63)(208), 6.415(54)(104), 3.162(43)(217). The chemical composition (electron microprobe, H 2 O calculated from X-ray diffraction data) is as follows, wt %: 12.69 Na 2 O, 3.53 K 2 O, 11.02 CaO, 0.98 SrO, 0.15 BaO, 5.33 FeO, 0.37 MnO, 0.07 Al 2 O 3 , 51.20 SiO 2 , 0.39 TiO 2 , 11.33 ZrO 2 , 0.21HfO 2 , 0.09 Nb 2 O 5 , 1.89 Cl, 0.93H 2 O, -O = Cl 2 0.43; total is 99.75. The empirical formula calculated on the basis of Si + Al + Zr + Hf + Ti + Nb = 29 ( Z = 3) is (Na 1l.75 Sr 0.29 Ba 0.03 ) Σ12.07 (K 2.28 Na 0.72 ) Σ3 Ca 5.99 (Fe 2.26 Mn 0.16 ) Σ2.42 (Zr 2.80 Ti 0.15 Hf 0.03 Nb 0.02 ) Σ3 (Si 1.96 Al 0.04 ) Σ2 [Si 3 O 9 ] 2 [Si 9 O 27 ] 2 [(OH) 1.42 O 0.58 ] Σ2 [Cl 1.62 (H 2 O) 0.38 ] Σ2 · 0.48H 2 O. The simplified formula is Na 12 K 3 Ca 6 Fe 3 2+ Zr 3 (Si 26 O 73 OH)Cl 2 . The IR-spectrum is given and the crystal structure is described. The position of davinciite in the crystal chemical taxonomy of the eudialyte group is shown, and its relationships with the other eudialyte-group minerals (acentric eudialyte, andrianovite, and kentbrooksite) are characterized. The type material of davinciite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

The structures of natural iron-rich eudialyte (specimen 3458 from the Khibiny massif, the Kola Peninsula) and two heat-treated samples of this mineral calcined at 700 and 800°C were determined by X-ray diffraction. The trigonal unit-cell parameters (sp. gr. R 3 m ) are as follows: a = 14.2645(1) Å, c = 29.9635(5) Å; a = 14.1307(1) Å, c = 30.1229(3) Å; a = 14.1921(2) Å, c = 30.2417(5) Å, respectively. It was found that Fe 3+ ions in the calcined eudialytes, as well as impurities in the starting specimen, occupy the square-pyramidal Fe 3+ (V) sites, whereas Fe 2+ ions are in the planar-tetragonal Fe 2+ (IV) sites.

The iron-rich variety of zanazziite Ca2[Mg0.65Fe0.35□1.0][Mg1.90Fe1.25Al0.5Mn0.35]Σ4Be4(PO4)6(OH)4(H2O,OH)2 · 4H2O, which is a heteropolyhedral framework roscherite-group beryllophos-phate from the Sapucaia pegmatite (Minas Gerais, Brazil), was studied by X-ray diffraction. The refinement was carried out in the triclinic and monoclinic systems. It was found that the cation distribution on octahedral sites in the crystal structure is in better agreement with the monoclinic symmetry (a = 15.876 Å, b = 11.860 Å, c = 6.607 Å, β = 95.49°, sp. gr. C2/c). In the sample under study, no ordering of Mg or Fe atoms in octahedral sites is observed in sp. gr. P \(\bar 1\), unlike the more iron-rich member of the roscherite group (atencioite).

The crystal structures of two unusual varieties of cancrinite-group minerals—oxalate-bearing cancrinite from the Kovdor massif (Kola Peninsula) and the sulfate end member of the davyne series from the Sar-e Sang mine (Badakhshan, Afghanistan)—were studied by single-crystal X-ray diffraction. The unit-cell parameters of the hexagonal cells are a = 12.688(4) Å, c = 5.189(1) Å and a = 12.773(1) Å, c = 5.334(1) Å, sp. gr. P 6 3 ; the R factors are 0.034 and 0.035, respectively. The presence of oxalate groups in cancrinite as admixtures is one of the factors responsible for the shift of CO 3 groups in wide channels.

The structure of a new representative of the eudialyte group with the formula (Na,Sr,K)18Ca6Zr3Fe[Si25O72](OH)2Cl · H2O from the Lovozero massif (Kola Peninsula) was studied by X-ray diffraction. The trigonal unit-cell parameters are a = 14.226 Å, c = 30.339 Å, sp. gr. R \(\bar 3\) m; the R factor is 0.045 based on 990 reflections. This sample is of interest as a sodium-rich and iron-poor mineral having a rare centrosymmetric structure, in which the M(2) site is occupied predominantly by sodium atoms. The dependence of the formation of centrosymmetric and non-centrosymmetric structures on the composition of eudialyte-group minerals was analyzed.

Fluorcanasite is described, a new mineral species found in dumps of the Kirovsk apatite mine, Mt. Kukisvumchorr, Khibiny alkaline pluton, Kola Peninsula, Russia. The new mineral is associated with microcline, nepheline, aegirine, scherbakovite, lamprophyllite, pectolite, mosandrite, villiaumite, rasvumite, and molybdenite. It occurs as prismatic crystals up to 0.2−0.3 × 1−2 mm in size extending along [010]. Fluorcanasite is purple, transparent, with white streak and vitreous luster. The fracture is hackly along the extension and stepped in other directions. The mineral is brittle. The cleavage is eminent parallel to {100} and {201} and perfect parallel to {001}. D (meas) = 2.68(2) g/cm 3 (volumetric method); D (calc) = 2.69 g/cm 3 . Fluorcanasite is biaxial, negative, n α = 1.538(1), n β = 1.546(1), n γ = 1.549(1), 2 V (meas) = 60(2)°, 2 V (calc) = 63°. Dispersion r > v . The new mineral is pleochroic according to the scheme N β > N γ > N α ; N β is purple, N γ is lilac, and N α is amber-yellow. Orientation is as follows: b = N β , a ∧ N γ = 3°, c ∧ N α = 19°. Fluorcanasite is not luminescent in UV light and slowly decomposes in acid. The new mineral is monoclinic, space group Cm , a = 18.846(4), b = 7.242(1), c = 12.650(2) Å, β = 111.84(2)°, V = 1602.6(4) Å 3 , Z = 2. The strongest reflections [ d , Å( I )] in the X-ray powder pattern of a grainoriented sample are 2.915(100), 4.204(40), 5.872(36), 4.712(36), 2.358(32), 3.012(24), 2.310(24), 3.082(24) and the same reflections in a randomly oriented sample are 3.082(100), 2.915(85), 4.712(46), 4.204(41), 3.340(35), 5.872(33), 2.658(30). The chemical composition, determined with an electron microprobe, is as follows, wt %: 7.19 Na 2 O, 10.91 K 2 O, 19.55 CaO, 0.27 FeO, 2.08 MnO, 55.84 SiO 2 , 4.10 F, 2.22 H 2 O (determined on the basis of structural data), 1.73-O = F 2 ; the total is 100.43. The empirical formula, calculated on the basis of Si = 12, is K 2.99 Na 3.00 (Ca 4.50 Mn 0.38 ·Fe 0.05 2+ ) Σ4.93 Si 12 O 29.93 (F 2.79 OH 1.21 ) Σ4 · 0.98H 2 O. The idealized formula is K 3 Na 3 Ca 5 Si 12 O 30 (F,OH) 4 · H 2 O, F > OH or K 3 Na 3 Ca 5 (Si 12 O 30 )F 4 · H 2 O. The IR spectrum of the mineral, description of its crystal structure, and comparison with its close analogues, canasite and frankamenite, are given in the paper. New optical parameters and crystal data are presented for the type specimen of canasite from the Materialnaya adit, Mt. Yukspor, Khibiny. Type material is deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

The structure of the mineral jinshajiangite from the Norra Kärr alkaline complex (Sweden) was determined by single-crystal X-ray diffraction and refined to R = 6.7%. The monoclinic unit-cell parameters are a = 5.350(2) Å, b = 6.909(6) Å, c = 20.96(1) Å, β = 99.83(4)°, sp. gr. P2/m. This mineral is an Fe-rich analogue of surkhobite and perraultite, but it crystallizes in a different space group, and the unit-cell parameters a and b are two times smaller than those of these two minerals. The framework of jinshajiangite from Norra Kärr contains narrow and wide channels, which are occupied by Ca, Na, Ba, and K atoms in an ordered fashion.

This paper presents the description of a new eudialyte-group mineral, which was named andrianovite in honor of Valerii Ivanovich Andrianov (1938–1991), a famous Russian mathematician and crystallographer, who developed the AREN software package for structural study of minerals with variable composition. The new mineral has been found in pegmatite from the Koashva open pit, Khibiny Pluton, Kola Peninsula, as rims 0.1–1.0 mm wide surrounding the crystals of typical eudialyte. Aegirine, sodalite, microcline, natrolite, lomonosovite, lamprophyllite, mosandrite, and villiaumite are associated minerals. Andrianovite is light yellow, with vitreous luster and stepped fracture. It is transparent or turbid, with a white streak. The new mineral is brittle; the Mohs hardness is 5. The cleavage is imperfect parallel to (001). The measured density is 2.93(2) g/cm3 (volumetric method); the calculated density is 3.02 g/cm3. Andrianovite is optically uniaxial, negative; ω = 1.622(2), ɛ= 1.617(2). It is nonfluorescent and nonpleochroic. The new mineral slowly breaks down and gelates in 50% HCl and HNO3 at room temperature. It is trigonal, space group R3m. The unit cell dimensions are a = 14.281(4), c = 30.243(7) Å, V = 5342(4) Å3. The strongest reflections in the X-ray powder pattern [d, Å (I, %)(hkl)] are as follows: 2.982(100)(315), 2.860(94)(404), 4.322(71)(205), 3.222(70)(208), 6.447(60)(104), 3.170(50)(217), 5.719(40)(202), 3.540(38)(027). The chemical composition (electron microprobe, H2O and CO2 determined by chemical analysis) is as follows, wt %: 11.61 Na2O, 2.05 K2O, 10.26 CaO, 3.11 SrO, 0.19 BaO, 3.97 MnO, 2.43 FeO, 0.81 La2O3, 1.73 Ce2O3, 0.52 Nd2O3, 0.28 Y2O3, 0.02 Al2O3, 47.06 SiO2, 0.12 TiO2, 11.32 ZrO2, 0.26 HfO2, 2.84 Nb2O5, 0.31 Cl, 0.57 CO2, 0.87 H2O, −O = 0.07 Cl2; total is 100.26. The empirical formula atcat = 53 (Z= 3) is Na12.09(K1.40Sr0.97REE0.60Ba0.04)Σ3.01(Ca5.90Y0.08).98(Mn1.81)Fe 1.19 2+ Σ2.90(Zr2.96Hf0.04)Σ3.0(Nb0.69Si0.27Ti0.05Al0.01)Σ1.02(Si25O73)[(O2.14(OH)0.52]Σ2.66[(H2O)1.30(CO3)0.42Cl0.28]Σ2.0. The simplified formula is Na12(K,Sr,Ce)3Ca6(Mn,Fe)3Zr3Nb(Si25O73)(O, H2O,OH)5. The infrared spectrum is given, and the crystal structure is described. The position of andrianovite in the crystallochemical taxonomy of the eudialyte group is shown, and its relationships with other eudialyte-group minerals (kentbrooksite, carbokentbrooksite, georgbarsanovite, etc.) are characterized. The type material of andrianovite has been deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.