American Mineralogist, Volume 95, pages 1357–1361, 2010 New Mineral Names* PAULA C. PIILONEN † AND GLENN POIRIER Mineral Sciences Division, Canadian Museum of Nature, P.O. Box 3443, Station D, Ottawa, Ontario K1P 6P4, Canada NEW MINERALS lines on the pattern [dobs in Å(Iobs%, hkl)] include: 3.712(13,111), 3.476(11,3.473), 3.075(25,201), 2.859(100,211), 2.4563(32,310), ALU M OÅKER M ANITE * 1.9413(11,400), 1.8303(13,330), 1.7634(11,411), 1.7569(19,312), D. Wiedenmann, A.N. Zaitsev, S.N. Britvin, S.V. Krivovichev, 1.7364(13,420), and 1.3859(13,521). The crystal structure of 2+ alumoåkermanite was solved and refined using a 0.22 × 0.14 × and J. Keller (2009) Alumoåkermanite, (Ca,Na)2(Al,Mg,Fe ) 0.12 mm crystal mounted on a Stoe IPDS II Image-Plate-based (Si2O7), a new mineral from the active carbonatite-nephelin- ite-phonolite volcano Oldoinyo Lengai, northern Tanzania. X-ray diffractometer. The structure was refined using starting Mineral. Mag., 73, 373–384. parameters from a synthetic sodic melilite (Louisnathan 1970, Z. Kristallogr., 23, 314–321) inverted to obtain the absolute correct Alumoåkermanite is a new member of the melilite group structure model. The data were refined to R1 = 0.018 based on from the Oldoinyo Lengai volcano, northern Tanzania. The 439 unique reflections with |Fo| ≥ 4σF. The mineral is tetrago- 3 new mineral was found in several samples from the volcano nal, P421m, a = 7.7620(7), c = 5.0311(5) Å, V = 303.12(5) Å , and surrounding area. It occurs in evolved, olivine-free melilite- Z = 2. The structural formula can thus be written as (Ca1.5Na0.5) nephelinitic ashes and lapilli-tuffs from the 1966/67 and pre-1966 (Al0.5Fe0.3Mg0.2)(Si2O7), which agrees with the WDS data. The eruptions along with nepheline, aegirine-augite, and microcrysts structure of alumoåkermanite is identical in topology to other of matrix-minerals including nepheline, aegirine-augite, combe- melilite-group minerals with [(Al,Mg)Si2O7)] sheets interwoven ite, spinel-group minerals, wollastonite, melanite, titanite, and with layers of (Ca,Na) cations. The absence of Al in the silicate sodalite. Alumoåkermanite occurs as tabular phenocrysts up 1.5 tetrahedra site is unique in alumoåkermanite. mm, and as microphenocrysts in the fine-grained groundmass. It The name is for its composition and relationship to other is transparent, light brown, has a white streak, a Mohs hardness members of the melilite group. The mineral and name have been of ~4.5–5, is brittle with an uneven fracture, and no discernible approved by the IMA CNMNC (IMA no. 2008-049). Co-type fracture or cleavage. It does not fluoresce in either short-wave specimens have been deposited in the Mineralogical Museum, 3 Department of Mineralogy, St. Petersburg State University, St. or long-wave UV light. It has a Dmeas = 2.96(2) g/cm and Dcalc = 3.00 g/cm3. Alumoåkermanite is uniaxial negative (–), with Petersburg, Russia (OL218, catalog no. 1/19407), and the Fers- ω = 1.635(1) for both samples, and ε = 1.626(1) (OL244) and man Mineralogical Museum, Russian Academy of Sciences, 1.624(2) (OL218). Under cross-polarized light, alumoåkermanite Moscow, Russia (OL244, catalog no. 3823/1). P.C.P. has a yellow to orange-red interference color, straight extinction, CÁ M ARAITE * positive elongation, and is non-pleochroic. The average chemical composition (WDS) of eight analyses E. Sokolova, Y. Abdu, F.C. Hawthorne, A.V. Stepanov, G.K. Bekenova, and P.E. Kotel’Nikov (2009) Cámaraite, Ba3NaTi4 gave SiO2 43.73, TiO2 0.09, Al2O3 8.32, Fe2O3 2.14, FeO 4.55, 2+ (Fe ,Mn)8(Si2O7)4O4(OH,F)7. I. A new Ti-silicate mineral MnO 0.22, MgO 4.36, CaO 30.24, SrO 0.91, Na2O 5.70, K2O from the Verkhnee Espe Deposit, Akjailyautas Mountains, 0.10, sum 100.23 wt%, corresponding to (Ca1.48Na0.50Sr0.02K0.01)Σ2.01 2+ 3+ Kazakhstan. Mineral. Mag., 73, 847–854. (Al0.44Mg0.30Fe 0.17Fe 0.07Mn0.01)Σ0.99(Si1.99Al0.01O7) based on seven 2+ oxygen atoms, and an ideal formula of (Ca,Na)2(Al,Mg,Fe ) F. Cámara, E. Sokolova, and F. Nieto (2009) Cámaraite, Ba3Na (Si2O7). 2+ Powder X-ray diffraction data were collected on a Stoe Stadi Ti4(Fe ,Mn)8(Si2O7)4O4(OH,F)7. II. The crystal structure and P diffractometer (CuKα radiation) in transmission geometry. Re- crystal chemistry of a new group-II Ti-disilicate mineral. fined unit-cell parameters for the powder X-ray diffraction data Mineral. Mag., 73, 855–870. are a = 7.7661(4), c = 5.0297(4) Å, V = 303.4(1) Å3. The strongest Cámaraite is a new mineral from the Verkhnee Espe rare- element deposit located at the northern exo-contact of the large *All minerals marked with an asterisk have been approved by Akjailyautas granite massif, northern Tarbagatai mountain range, the IMA CNMMC. eastern Kazakhstan. It was found within a part of the deposit † E-mail: [email protected] where alkali-rich fenites have been extensively recrystallized. 0003-004X/10/0809–1357$05.00/DOI: 10.2138/am.2010.565 1357 1358 NEW MINERAL NAMES Cámaraite is a hydrothermal mineral and occurs along with mineralogy and crystallography, particularly with respect to Ti- bafertisite, jinshajiangite, zircon, pyrochlore-group minerals, silicates, amphiboles, arrojadite-group minerals and cancrinite- thorite, monazite, and xenotime at the exo-contact of the fen- group minerals. The mineral and name have been approved by itized and granitized host rock. The mineral occurs on fracture IMA CNMNC (IMA no. 2009-11). Holotype material has been surfaces, intergrown with jinshajiangite and bafertisite (8 × 15 deposited at the Fersman Mineralogical Museum, Moscow, × 2 mm intergrowths), and as star-shaped aggregates of crystals. Russia (catalog no. 3828/1 and 3828/2). P.C.P. Cámaraite is orange-red to brownish-red, platy on {001}, has a pale-yellow streak, a vitreous luster, is brittle with a {001} DALIRANITE * cleavage, no observed parting, a Mohs hardness of <5, and does W.H. Paar, A. Pring, Y. Moëlo, C.J. Stanley, H. Putz, D. Topa, not fluoresce under cathode or UV light. The mineral has Dmeas A.C. Roberts, and R.S.W. Braithwaite (2009) Daliranite, 3 = 3.871(1) and Dcalc = 4.018 g/cm . Cámaraite is biaxial positive PbHgAs2S6, a new sulfosalt from the Zarshouran Au-As (+), 2Vmeas = 93(1)°, with refractive indices > 1.80 (rcalc = 1.866). deposit, Takab region, Iran. Mineral. Mag., 73, 871–881. It is strongly pleochroic, X = light brown, Y = reddish brown, Z = yellow-brown, Z < X < Y. Daliranite is a new sulfosalt mineral from the Zarshouran Au- The chemical composition of cámaraite was determined As deposit, 42 km north of the town of Takab, West Azarbaijan by WDS methods with the average (range) of 13 analyses Province, northwest Iran. The mineral has been known from this giving Nb2O5 1.57(1.36–1.82), SiO2 25.25(25.09–25.40), locality since the 1970s, often mislabeled as ludlockite, which it TiO2 15.69(15.41–15.88), ZrO2 0.33(0.22–0.52), Al2O3 resembles. Daliranite occurs growing on orpiment and quartz, 0.13(0.09–0.22), Fe2O3 = 2.77, FeOtot 16.54(18.76–19.37), MnO or, rarely, as matted nests along cracks and fractures. The matted 9.46(9.34–9.60), ZnO 0.12(0.09–0.17), MgO 0.21(0.20–0.22), nests consist of acicular, flexible hair-like fibers <200 μm long CaO 0.56(0.48–0.70), BaO 21.11(20.60–21.66), Na2O 1.41(1.32– and <3μm in diameter elongated parallel to [010]. The mineral 1.48), K2O 0.84(0.80–0.89), H2Ocalc 1.84, F 3.11(2.93–3.33), is vibrant orange-red, has a pale orange-red streak, is transpar- O≡F –1.31, sum 99.63 wt%, corresponding to the empirical ent with an adamantine luster, and has a Mohs hardness of >2. formula based on 39 anions of (Ba2.61K0.34)Σ2.95(Na0.86Ca0.14)Σ1 Neither cleavage nor fracture was observed, nor is it fluorescent. 2+ 3+ (Ti3.72Nb0.22Al0.05)Σ3.99(Fe 4.36Fe 0.66Mn2.53Mg0.10Zr0.05Zn0.03Ca0.05)Σ7.78 Optically, daliranite has a gray color with a distinctly higher re- 2+ Si7.97O35.89H3.88F3.11, ideally Ba3NaTi4(Fe ,Mn)8(Si2O7)4O4 flectance than that of orpiment and abundant orange-red internal 57 (OH,F)7. Mössbauer spectroscopy (RT, Co source) allowed reflections. Reflectance data were determined in air (%/nm): 3+ for the determination of the Fe /Fetot ratio [0.13(8)] and the 32.9/470, 30.5/546, 34.0/589, and 39.5/650. confirmation that all Fe is octahedrally coordinated. Chemical analyses of daliranite (EMPA) gave an average Powder X-ray diffraction data were collected on a 57.3 mm composition (eight analyses) of Pb 23.26, Hg 24.77, Tl 0.19, As Debye-Scherrer camera (CoKα radiation). Refined unit-cell 18.75, S 22.48, sum 89.44%, resulting in an empirical formula parameters are a = 10.678(4), b = 13.744(8), c = 21.40(2) Å, based on 10 apfu (and after normalizing the EMPA data) of 3 α = 99.28(8), β = 92.38(5), γ = 90.00(6)°, V = 3096(3) Å . The Pb0.95Tl0.01Hg1.04As2.10S5.91, with an ideal formula of PbHgAs2S6, strongest lines in the diffraction pattern [dobs in Å(Iobs%, hkl)] which requires Pb 27.63, Hg 26.75, As 19.98, S 25.65, sum are: 3.83(30,204), 3.39(50,224), 3.26(20,043), 3.18(50,2 25), 100.00 wt%.