OH,F) 7 , is a new mineral from the Verkhnee Espe deposit, Akjailyautas Mountains, Kazakhstan. It occurs as intergrowths with bafertisite and jinshajiangite in separate platy crystals up to 8 mm615 mm62 mm in size, or as star-shaped aggregates of crystals with different orientations. Individual crystals are orange-red to brownish-red, and are platy on {001}. Cámaraite is translucent and has a pale-yellow streak, a vitreous lustre, and does not fluoresce under cathode or ultraviolet light. Cleavage is {001} perfect, no parting was observed, and Mohs hardness is <5; the mineral is brittle. The calculated density is 4.018 g cm À3 . In transmitted light, cámaraite is strongly pleochroic, X = light brown, Y = reddish-brown, Z = yellowbrown, with Z < X < Y. Cámaraite is biaxial +ve and 2V meas. = 93(1)º. All refractive indices are greater than 1.80. Cámaraite is triclinic, space group C1, a = 10.678 (4) Å , b = 13.744(8) Å , c = 21.40(2) Å , a = 99.28(8)º, b = 92.38(5)º, g = 90.00(6)º, V = 3096(3) Å 3 , Z = 4, a:b:c = 0.7761:1:1.5565. The seven strongest lines in the X-ray powder-diffraction pattern are as follows: [d (99.63 wt.%, where the valence state of Fe was determined by Mössbauer spectroscopy [Fe 3+ /(Fe 2+ + Fe 3+ ) = 0.13(8)] and the H 2 O content was derived by crystal-structure determination. The resulting empirical formula on the basis of 39 anions is

Karchevskyite, a new mineral related to the family of layered double hydroxides (LDHs), has been found in the Iron open pit at the Kovdor carbonatite massif, Kola Peninsula, Russia. The mineral occurs as spherulites of up to 1.5 mm in diameter composed of thin, curved lamellae. Dolomite, magnetite, quintinite-3 T , strontium carbonate, and fluorapatite are associated minerals. Karchevskyite is white in aggregates and colorless in separate platelets. Its luster is vitreous with a pearly shine on the cleavage surface. The new mineral is nonfluorescent. The Mohs hardness is 2. The cleavage is eminent (micalike), parallel to {001}. The measured density is 2.21(2) g/cm 3 , and the calculated value is 2.18(1) g/cm 3 . Karchevskyite is colorless and nonpleochroic in immersion liquids. It is uniaxial, negative, ω = 1.542(2), and ε = 1.534(2). The chemical composition (electron microprobe, average of ten point analyses, standard deviation in parentheses, wt %) is as follows:14.5(0.4) CO 2 , and 28.6 H 2 O (estimated by difference); the total is 100. The empirical formula calculated on the basis of nine Al atoms is Mg 18.00 Al 9.00 (OH) 54.00 (Sr 1.79 Mg 0.48 Ca 0.09 ) 2.36 (Ca 3 ) 8.26 (PO 4 ) 0.46 (H 2 O) 6.54 (H 3 O) 4.18 . The idealized formula is [Mg 18 Al 9 (OH) 54 ][Sr 2 (CO 3 , PO 4 ) 9 (H 2 O, H 3 O) 11 ]. The new mineral slowly dissolves in 10% HCl with weak effervescence. Karchevskyite is trigonal; possible space groups are P 3, P 3, P 1 m , P 31 m , P 312, P 312, P 3 m 1, or P 3 m 1; unit-cell dimensions are a = 16.055(6), c = 25.66(1) Å, V = 5728(7) Å 3 , Z = 3. The strongest reflections in the X-ray powder diffraction pattern [ d , ( I , %)( hkl )] are: 8.. Wavenumbers of absorption bands in the infrared spectrum of the new mineral are (cm -1 ; s is shoulder): 3470 , 3420s, 3035, 2960s, 1650, 1426, 1366, 1024, 937, 860, 779, 678, 615s, 553, 449, 386. Results of thermogravimetric analysis: total weight loss is 42.0 wt %, with three stages of loss: 12.2%, maximum rate at 230 ° C; 6.1%, maximum rate at 320 ° C; and 23.7%, maximum rate at 440 ° C. Karchevskyite is a late-stage hydrothermal mineral. The mineral is named in memory of Russian mineralogist Pavel Karchevsky (1976, who made a significant contribution to the study of carbonatites. The type material of karchevskyite is deposited at the Mineralogical Museum, Division of Mineralogy, St. Petersburg State University, and the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

No abstract

Fluoroleakeite, NaNa2(Mg2Fe3+2Li)Si8O22F2 is a new mineral of the amphibole group from the Verkhnee Espe deposit, Akjailyautas mountains, eastern Kazakhstan district, Kazakhstan. The granites and their host rocks have been intensely reworked by post-magmatic and host-rock fluids, resulting in intense recrystallization, enrichment in F, Li and rare elements, and replacement of primary biotite and sodic-calcic amphiboles by Li-bearing riebeckite, aegirine, astrophyllite and other sodic minerals including fluoroleakeite. Crystals are prismatic parallel to [001] with {100} and {110} faces and cleavage surfaces, and the prism direction is terminated by irregular fractures. Grains are up to 3 mm long, and occur as isolated crystals, as small aggregates, and as inclusions in cámaraite. Crystals are black with a very pale grey to colourless streak. Fluoroleakeite is brittle, has a Mohs hardness of 6 and a splintery fracture; it is non-fluorescent with perfect {110} cleavage, no observable parting, and has a calculated density of 3.245 g cm–3. In plane-polarized light, it is pleochroic, X = pale grey-green, Y = medium grey, Z = grey-brown; X^a = 14.1° (in β obtuse), Y ‖ b, Z^c = 75.9° (in β acute). Fluoroleakeite is biaxial negative, α = 1.663(2), β = 1.673(2), γ = 1.680(2); 2Vobs = 80.9(6)°, 2Vcalc = 79.4°Fluoro-leakeite is monoclinic, space group C2/m, a = 9.8927(3), b = 17.9257(6), c = 5.2969(2) Å, β = 103.990(1)°, V = 905.7(1) Å3, Z = 2. The strongest ten X-ray diffraction lines in the powder pattern are [d in Å(I)(hkl)]: 2.718(100)(151), 8.434(40)(110), 4.464(30)(021), 3.405(30)(131), 3.137(20)(310), 2.541(20)(), 2.166(20)(261), 2.325(15)(), 2.275(15)() and 2.806(10)(330). Analysis by a combination of electron microprobe and crystal-structure refinement gives SiO2 53.34, Al2O3 0.62, TiO2 1.27, V2O3 0.05, Fe2O3 15.10, FeO 6.00, MnO 2.04, ZnO 0.18, MgO 6.40, CaO 0.13, Na2O 9.08, K2O 1.98, Li2O 1.10, F 3.33, H2Ocalc 0.16, sum 99.39 wt.%. The formula unit, calculated on the basis of 23 O, is A(Na0.64K0.38)(Na1.98Ca0.02)(Li0.66Mg1.42Fe0.752+Mn0.262+Zn0.02Fe1.693+V0.013+Ti0.144+Al0.03) (Si7.93Al0.07)O22(F1.57OH0.16O0.27). Crystal-structure refinement shows Li to be completely ordered at the M(3) site. Fluoroleakeite, ideally NaNa2(Mg2Fe23+Li)Si8O22F2, is related to end-member leakeite, NaNa2(Mg2Fe23+Li)Si8O22(OH)2 by the substitution F → (OH).

Natrotitanite, ideally (Na0.5Y0.5)Ti(SiO4)O, is a new mineral from the Verkhnee Espe rare-element deposit at the northern exo-contact of the Akjailyautas granite massif in the northern part of the Tarbagatai mountain range, Eastern Kazakhstan. Both the mineral and the name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2010-033). Star-shaped aggregates of small short prisms of yellow or yellowish white (Na,Y,REE)-bearing titanite rimmed by thin (∼2 μm) rims of natrotitanite are embedded in yttrium-bearing fluorite and replace narsarsukite. Associated minerals are microcline, albite, quartz, riebeckite, aegirine, biotite, astrophyllite, rutile, zircon and elpidite. Natrotitanite is milky white to yellowish grey, transparent to translucent, and has a white streak and a vitreous lustre. It shows pale orange cathodoluminescence but does not fluoresce under ultraviolet light. It shows no cleavage or parting, and is brittle; the calculated density is 3.833 g cm–3. The indices of refraction, measured with the Bloss spindle stage for the wavelength 590 nm using a gel filter, are α = 1.904, γ = 2.030, and these values are in accord with the mean refractive index, 1.988, calculated from the Gladstone-Dale relation. Natrotitanite is monoclinic, C2/c, a = 6.5691(2), b = 8.6869(3), c = 7.0924(2) Å, β = 114.1269(4)°, V = 369.4(2) Å3, Z = 4, a:b:c = 0.7562:1: 0.8164. The seven strongest lines in the X-ray powder diffraction pattern [in the order d (Å), I, (hkl)] are as follows: 2.597, 10, (130); 3.248, 8, (11); 2.994, 6, (200); 1.641, 4, (330); 4.941, 3, (110); 1.498, 3, (400); 2.273, 3, (11). Chemical analysis by electron microprobe gave Nb2O5 1.28, SiO2 27.83, TiO2 35.00, SnO2 0.57, V2O3 0.36, Fe2O3 0.23, Y2O3 7.87, Ce2O3 0.83, Sm2O3 0.26, Gd2O3 0.46, Tb2O3 0.17, Dy2O3 2.45, Ho2O3 0.16, Er2O3 2.24, Tm2O3 0.50, Yb2O3 2.53, Nd2O3 0.35, Lu2O3 0.28, MnO 0.33, CaO 8.16, Na2O 5.55, F 1.52 O ≡ F –0.64, sum 98.71 wt.%. The resulting empirical formula is (Na0.39Ca0.32Y0.15Dy0.03Yb0.03Er0.03Ce0.01Ho0.01Tm0.01Gd0.01Nd0.01)Σ1.00(Ti0.95Nb0.02Sn0.01Fe3+0.01Mn0.01V0.01)Σ1.01Si1.01O4.00(O0.83F0.17), calculated on the basis of 3 cations per formula unit. The general formula is written as (Na,Ca,Y,REE)TiSiO4(O,F), and the endmember formula is (Na0.5Y0.5)Ti(SiO4)O.The crystal structure of a composite optically continuous crystal of natrotitanite and (Na, Y)-bearing titanite was mounted on a Bruker D8 three-circle diffractometer equipped with a rotating anode generator (MoKα radiation), a multi-layer optics incident-beam path and an APEX-II CCD detector. The crystal structure was refined in space group C2/c to a final R1 index of 1.8%. Natrotitanite is isostructural with titanite, (Na + Y + REE) replacing Ca at the Ca site in the titanite structure.