Lanthanite-(Ce), (Ce,La,Nd)2(CO3)3 · 8H2O, a new mineral from Wales, U.K.
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Lanthanite-(Ce) occurs as a secondary mineral in oxidized copper ore at the Britannia Mine, Snowdoni4 North Wales, U.K. It is found as colorless transparent plates {010} covered by radiating tufts of malachite and is associated with brochantite, posnjakite and chalcoalumite. The analytical formula, based on t7 oxygens, is (Ce6.rrl-ao.rrNdo.rrSmo.oGdo.orYo.oohr.ouCz.rOg.ot'7.96H2O, and the theoretical formula is (Ce,La,Nd)r(CO3)3.8H2O with Ce > La,Nd. Orthorhombic, space goup Pbnb, a:9.482(6), b : 16.938(ll), c : 8.965(3)A,Z:4, D(calc.) :2.79 E/carr for the ideal formula (Ce:La:Nd : 0.83 :0.59 :0.58), D (meas .l : 2.76 g/cmt , V : 144043, a:brc :0.559E :1 :0.5293. Strongest lines in the X-ray powder diffraction pauern are ftlA (I) (hkl)l 8.47(100X020), 4.746(65)l2W),4.462(62NW2),3.255(73N202) and 3.028(65\222\. The mineral is biaxial negative, a 1.532(2), P 1.594(2),y l.6lQ2); orientation X:b, Y:c, Z:a;2V(measJ:60(2)0, 2V(calc.)=62,no dispersion observed. The mineral is not fluorescent, and has H:2.5, a colorless streak, a vitreous luster and is sectile. In dilute mineral acids (HCl, HNO.), the mineral reacts with effervescence to yield a gel-like precipitate oflanthanide(Ill) hydroxides.Keywords:
Malachite
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The crystal structure of lanthanite, (La,Ce).(C03k 8H20, a=9.504(4), b= 16.943(6), c=8.937(5) A; space group Pbnb, Z=4, has been determined by Patterson and Fourier methods using 1022 intensities measured with an automatic diffractometer. The hydrogen atoms belonging to three of the four independent water molecules have been located in the difference Fourier map. The least-squares refinement led to a final R index of 0.025. The principal structural feature of lanthanite consists of infinite layers of RE-O coordination polyhedra and CO. 2 - groups. These layers are parallel to the ac plane and are connected to one another only by hydrogen bonds. This feature accounts for the micaceous {01O} cleavage.
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Braithwaiteite, NaCu 5 (Ti 4+ Sb 5+ )O 2 (As 5+ O 4 ) 4 [As 5+ O 3 (OH)] 2 (H 2 O) 8 , is a new and very rare secondary mineral of copper, discovered in the supergene zone of an epithermal Cu–Au–Ag deposit at Laurani, near Sica Sica, Bolivia. This deposit is the type locality for lammerite, described as a new species in 1981. Braithwaiteite is closely associated with lammerite, lavendulan– lemanskiite and quartz. It formed by oxidation of Sb-bearing enargite in an arid environment. Traces of pyrite, covellite, anatase, albite–oligoclase, kaolinite and a mineral of the chlorite group are present as well. Electron-microprobe analysis gives Na 2 O 1.7, CuO 25.8, FeO 0.2, TiO 2 4.5, Sb 2 O 5 11.7, As 2 O 5 42.3, H 2 O (calc.) 10.17, for a total of 96.37 wt.%. The empirical formula based on the results of crystal-structure solution and refinement [34 anions and 2(OH) + 8H 2 O] is Na 0.87 Cu 2+ 5.17 (Ti 4+ 0.90 Sb 5+ 1.15 ) ∑2.05 O 2 (As 5+ 0.98 O 4 ) 4 [As 5+ 0.98 O 3 (OH)] 2 (H 2 O) 8 . The simplified formula is NaCu 5 (TiSb)O 2 (AsO 4 ) 4 [AsO 3 (OH)] 2 (H 2 O) 8 , which requires Na 2 O 2.04, CuO 26.13, TiO 2 5.25, Sb 2 O 5 10.63, As 2 O 5 45.30, H 2 O 10.65, total 100.00 wt.%. Infrared spectroscopy indicates the presence of H 2 O and OH, and As–O and As–OH stretching vibrations. Single-crystal X-ray studies show braithwaiteite to be triclinic, space group P 1, a 7.0308(4), b 9.8823(5), c 10.6754(6) A, α 106.973(1), β 104.274(1), γ 93.839(1)°, V 679.76(11) A 3 , Z = 1, and a:b:c = 0.7115:1:1.0803. The strongest seven X-ray powder-diffraction lines [ d in A(I)( hkl )] are: 9.825(100)(001), 5.887(50)(011), 4.635(30)(102), 3.354(30)(122), 3.232(30)(211), 2.947(60)(022), 2.736(30)(222). Two crystals of braithwaiteite were found, one on matrix and the other loose, each of them less than 1 mm in size, plus a few very minute fragments. The forms that could be determined with certainty include the following pinacoids: {001} dominant, {010} less prominent, {100}, {103} and {203}, all subordinate. The crystals are transparent and have a sky-blue color, a vitreous luster and a very pale blue streak. Braithwaiteite is brittle and has a perfect cleavage parallel to {001}. Optically, braithwaiteite is biaxial negative, 2 V meas 59(2), 2 V calc 65°. Indices of refraction are α 1.698(2), β 1.757(5), γ 1.783(5) at 589.3 nm. The mineral is weakly pleochroic with pale blue to greenish blue hues. The hardness (Mohs) is ~2. Using the empirical formula and the unit-cell parameters derived from the single-crystal study, the calculated density is 3.753 g cm −3 . Braithwaiteite is named after Dr. Richard S.W. Braithwaite (born 1930), prominent chemist and mineralogist at the University of Manchester, U.K. The mineral and mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification, IMA (2006–050).
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Palygorskite
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Cerite-(La), ideally (La,Ce,Ca) 9 (Fe,Ca,Mg)(SiO 4 ) 3 [SiO 3 (OH)] 4 (OH) 3 , was found in an aegirine – natrolite – microcline vein in foyaite, Mt. Yuksporr, Khibina massif, Kola Peninsula, Russia. It forms porous pseudomorphs (up to 7 cm long) after an unidentified hexagonal prismatic mineral. Within the pseudomorphs, cerite-(La) occurs as a boxwork-like aggregates of equant to tabular crystals (flattened on c , up to 2 mm across), with dominant rhombohedral and pinacoidal faces. Associated minerals are aegirine, anatase, ancylite-(Ce), barylite, catapleiite, cerite-(Ce), chabazite-Ca, edingtonite, fluorapatite, galena, ilmenite, microcline, natrolite, sphalerite, strontianite and vanadinite. The mineral is brittle, with a conchoidal fracture. It is light yellow to pinkish brown with a white streak, and translucent with a vitreous luster. Cleavage and parting were not observed. The Mohs hardness is 5; the density is 4.7(1) g cm −3 (meas.) and 4.74 g cm −3 (calc.). It is uniaxial, optically positive, n o 1.810(5), n e 1.820(5) (for λ = 589 nm). An average result of seven electron-microprobe analyses for seven different crystals (each one reported as an average of 6–10 points from each crystal) gave La 2 O 3 37.57, Ce 2 O 3 23.67, Pr 2 O 3 0.61, Nd 2 O 3 1.48, Sm 2 O 3 0.10, Gd 2 O 3 0.24, SrO 1.97, CaO 5.09, Fe 2 O 3 1.40, MgO 0.51, SiO 2 22.38, P 2 O 5 0.63, H 2 O 3.20 (determined by the Penfield method), total 98.85, which corresponds to the empirical formula (La 4.23 Ce 2.65 Ca 1.37 Sr 0.35 Nd 0.16 Pr 0.07 Gd 0.02 Sm 0.01 ) ∑8.86 (Fe 0.32 Ca 0.30 Mg 0.23 ) ∑0.85 [SiO 4 ] 3 [(Si 0.84 P 0.16 ) ∑1.00 O 3 (OH)] 4 (OH) 2.78 , calculated on the basis of (Si + P) = 7. The mineral is trigonal, R 3 c , with a 10.7493 (6), c 38.318 (3) A, V 3834.36 A 3 , Z = 6. The strongest eight lines in the X-ray powder-diffraction pattern [ d in A( I )( hkl )] are: 3.53(26)(10.10,211), 3.47(40)(122), 3.31(38)(214), 3.10(25)(300), 2.958(100)(02.10), 2.833(37)(128), 2.689(34)(220), 1.949(34)(238,13.13). The crystal structure has been refined on the basis of F 2 for all unique reflections collected using a CCD area detector, to an R 1 of 0.036, calculated for the 1544 unique observed reflections ( F o ≥ 4σ F o ). Cerite-(La) is structurally related to cerite-(Ce). The mineral is named as the La-dominant analogue of cerite-(Ce). The structural formula for these minerals can be written as REE 9 M Ca x [SiO 4 ] 3 [SiO 3 ((OH) 1− x O x )] 3 [SiO 3 (OH)] 1− x (OH) 3 , where REE stands for La or Ce, and where M represents Fe, Mg, Ca.
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Abstract Mendeleevite-(Nd), (Cs,□) 6 (□,Cs) 6 (□,K) 6 ( REE ,Ca) 30 (Si 70 O 175 )(OH,H 2 O,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-(Nd), 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; D meas . = 3.20(2) g/cm 3 , D calc. = 3.155 g/cm 3 . Mendeleevite-(Nd) is optically isotropic, with the refractive index n = 1.582(2). Mendeleevite-(Nd) is cubic, space group Pm 3̄, 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 SiO 2 42.30, Ce 2 O 3 10.12, La 2 O 3 3.60, Nd 2 O 3 16.19, Pr 2 O 3 2.79, Sm 2 O 3 4.19, Gd 2 O 3 1.69, Eu 2 O 3 0.47, SrO 2.99, CaO 2.20, Cs 2 O 8.50, K 2 O 0.85, H 2 O 3.85, F 1.25, –O = F 2 –0.53, sum 100.46 wt.%, with H 2 O calculated by analogy with mendeleevite-(Ce). The empirical formula based on 210 (O + F) apfu, with F + OH + H 2 O = 35 pfu, is Cs 6 (□ 4.20 K 1.80 ) ∑6 {[(Nd 9.57 Ce 6.13 Sm 2.39 La 2.20 Pr 1.68 Gd 0.93 Eu 0.27 ) ∑23.17 (Ca 3.90 Sr 2.87 ) ∑6.77 ] ∑29.94 □ 0.06 } ∑30 (Si 70.03 O 175 )(OH 14.47 F 6.54 ) ∑21.01 (H 2 O) 14 , Z = 2. The simplified and ideal formulae are (Cs,□) 6 (□,Cs) 6 (□,K) 6 ( REE ,Ca) 30 (Si 70 O 175 )(OH, H 2 O,F) 35 and Cs 6 ( REE 23 Ca 7 )(Si 70 O 175 )(OH,F) 19 (H 2 O) 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 (Si 70 O 175 )(H 2 O,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.
Fluorite
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Fluoro-potassichastingsite, ideally KCa2(Fe2+4Fe3+)Si6Al2O22F2, is found in compact aggregates of crystals up to 1 cm size on the waste-rock dump at the Greenwood mine, in Harriman State Park, Tuxedo, Orange County, New York, USA. It is associated with magnetite, diopside, enstatite, pyrrhotite, chalcopyrite, pyrite and, rarely, phlogopite. Fluoro-potassichastingsite is transparent, black to greenish in very thin fragments, and non-fluorescent in ultraviolet light; it has a vitreous luster and a greenish gray streak. The Mohs hardness is 6, Dmeas is 3.289 g/cm3, and Dcalc is 3.37 g/cm3. The {110} cleavage is perfect, and the fracture is conchoidal. It is biaxial negative, with α 1.668(2), β 1.688(2), γ 1.698(2), 2 V meas 40–70°, 2 V calc 70°, Y = b , Z ∧ c = 23°, and r < v . The observed pleochroism is X bluish green, Y green to brownish green, Z blue to light blue. The Gladstone– Dale compatibility index is superior, with 1 – ( K P/ K C) = 0.012 (based on empirical formula and calculated density). The mineral is monoclinic, space group C 2/ m , a 9.9480(3), b 18.1777(6), c 5.3302(2) A, β 105.140(1)°, V 930.41(8) A3, and Z = 2. The strongest eight X-ray powder-diffraction lines [ d in A( I )( hkl )] are: 8.499(100)(110), 3.151(76)(310), 2.830 (53)(330), 3.299(32) (240), 2.722(23)(151), 2.402(17)(350), 3.401(11)(131), and 1.661(10)(461). Combined electron-microprobe and Mossbauer data yield: SiO2 40.49, TiO2 0.11, Al2O3 10.29, V2O3 0.03, Cr2O3 0.01, Fe2O3 4.49, FeO 19.80, CaO 11.13, MgO 6.68, MnO 0.20, K2O 2.93, Na2O 1.24, F 2.23, Cl 0.61, H2O 0.70, O = (F+Cl) −1.08, sum 99.86 wt.%, which corresponds to the following crystal-chemical formula based on 24 [O + (OH) + F + Cl]: A (K0.59Na0.25)∑0.84 B (Ca1.87Na0.13)∑2.00 C (Fe2+2.60Mg1.56Fe3+0.53Al0.26 Mn0.03Ti0.01)∑4.99 T (Si6.36Al1.64)∑8.00 O22.68O3[F1.11(OH)0.73Cl0.16]∑2.00. The ICP–MS analyses on a crystal fragment different than the one analyzed for major elements yielded the following trace-element concentrations (ppm): Cu 278.9, Rb 162.5, Y 343.2, La 257, Ce 568, Nd 156. The new species and name have been approved by IMA–CNMMN (2005–006).
Amphibole
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Abstract The new mineral, dyrnaesite-(La), is found in the Ilímaussaq alkaline complex, South Greenland. The holotype material originates from an arfvedsonite lujavrite sheet as an accessory mineral. Dyrnaesite-(La) is pale yellowish green, with no cleavage and an irregular fracture. Density is 3.68(2)/3.682 g/cm 3 (measured/ calculated). It is biaxial, negative, 2Vα = 47(1)/48 (measured/calculated); α = 1.6226(5), β = 1.6852(10), γ = 1.6982(2); X = c , Y = a , Z = b . The average values of microprobe analyses are (wt.%) P 2 O 5 37.17, SiO 2 0.15, CaO 0.90, Na 2 O 20.06, La 2 O 3 16.44, CeO 2 20.23, Pr 2 O 3 1.40, Nd 2 O 3 3.47, Sm 2 O 3 0.24, Dy 2 O 3 0.06, Y 2 O 3 0.06. The crystal structure was solved from single-crystal X-ray diffraction data. Dyrnaesite-(La) is orthorhombic, Pnma ; a = 18.4662(7) Å, b = 16.0106(5) Å, c = 7.0274(2) Å, V = 2077.7(2) Å 3 , Z = 4. The structural formula calculated from the diffraction data and microprobe analysis is Na 7.89 (Ce 0.94 Ca 0.06 ) ∑1.00 (Ca 0.12 La 1.14 Ce 0.40 Pr 0.10 Nd 0.24 ) ∑2.00 (PO 4 ) 6 , the simplified formula is Na 8 Ce 4+ REE 2 (PO 4 ) 6 . The crystal structure is related closely to that of vitusite-(Ce), but is distinct from it in several aspects. The five strongest lines of the powder X-ray diffraction pattern are (d Å, (I %), (hkl)); 6.57 (100) (101), 4.62 (40) (301, 230, 400), 3.50 (40) (331), 2.80 (86) (232, 402), 2.67 (54) (060,630).
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Aegirine
Peralkaline rock
Pegmatite
Fluorite
Molybdenite
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A new cerite group mineral species, taipingite-(Ce), ideally (Ce73+, Ca2)Σ9Mg(SiO4)3[SiO3(OH)]4F3, has been found in the Taipingzhen rare earth element (REE) deposit in the North Qinling Orogen (NQO), Central China. It forms subhedral grains (up to approximately 100 μm × 200 μm) commonly intergrown with the REE mineral assemblages and is closely associated with allanite-(Ce), gatelite-(Ce), törnebohmite-(Ce), fluocerite-(Ce), fluocerite-(La), fluorite, bastnäsite-(Ce), parisite-(Ce) and calcite. Taipingite-(Ce) is light red to pinkish brown under a binocular microscope and pale brown to colorless in thin section, and it is translucent to transparent with a grayish-white streak and vitreous luster. This mineral is brittle with conchoidal fracture; has a Mohs hardness value of approximately 5½ and exhibits no cleavage twinning or parting. The calculated density is 4.900(5) g/cm3. Optically, taipingite-(Ce) is uniaxial (+), with ω = 1.808(5), ε = 1.812(7), c = ε, and a = b = ω. Furthermore, this mineral is insoluble in HCl, HNO3 and H2SO4. Electron microprobe analysis demonstrated that the sample was relatively pure, yielding the empirical formula (with calculated H2O): (Ce4.02La1.64Nd1.49Pr0.41Sm0.10Gd0.02Ho0.02Tm0.01Lu0.02Y0.03Ca0.66Mg0.05Th0.01–0.51)Σ9(Mg0.75Fe0.253+)Σ1(SiO4)3{[SiO3(OH)]3.98[PO3(OH)]0.02}Σ4(F1.81OH1.17Cl0.02)Σ3. Taipingite-(Ce) is trigonal and exhibits space group symmetry R3c with unit cell parameters a = 10.7246(3) Å, c = 37.9528(14) Å, V = 3780.39(20) Å3 and Z = 6. The strongest eight lines in the X-ray diffraction pattern are [d in Å(I)(hkl)]: 4.518(50)(202), 3.455(95)(122), 3.297(85)(214), 3.098(35)(300), 2.941(100)(02,10), 2.683(65)(220), 1.945(40)(238) and 1.754(40)(30,18). The crystal structure has been refined to a R1 factor of 0.025, calculated for the 2312 unique observed reflections (Fo ≥ 4σ). The mineral is named after its discovery locality and is characterized as the F-dominant analogue of cerite-(Ce).
Allanite
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