ALBERT

Beschreibung: Bariopharmacoalumite, ideally Ba0.5Al4(AsO4)3(OH)4{middle dot}4H2O, is a new mineral from Cap Garonne, France. It occurs in several places within the mine as colourless to pale yellow interpenetrating cubes up to 0.5 mm across. Bariopharmacoalumite is transparent to translucent, with a white streak, has an adamantine lustre and imperfect cleavage on {001}. The Vickers hardness is 234.35 and the Mohs harness is 3.5. Bariopharmacoalumite is isotropic, with n = 1.573 (upper estimate) [calculated from reflectance values at 589 nm using Fresnel Equations]. The empirical formula, based on 20 oxygen atoms, is: (Ba0.54Cu0.03K0.01){Sigma}0.58(Al3.99Fe0.02){Sigma}4.01(AsO4)3.00(OH)3.85O0.15{middle dot}4H2O and the calculated density (on the basis of the empirical formula and single-crystal unit cell) is 2.580 g/cm3. The four strongest lines in the X-ray powder diffraction pattern are [dobs(A), Iobs,(hkl)]: 7.759, 100, (001); 5.485, 27, (011); 3.878, 27, (002); 4.454, 18, (011). Bariopharmacoalumite from Cap Garonne is cubic, space group P[IMG]f1.gif" ALT="Formula" BORDER="0"〉3m with a = 7.742(4) A, V = 464.2(4) A3 and Z = 1. The crystal structure was solved by direct methods and refined to R1 = 0.0705 for 215 reflections with I 〉 4{sigma}(I) and is consistent with members of the pharmacosiderite supergroup. Data are also presented from zoned bariopharmacoalumite-bariopharmacosiderite crystals found at the Mina Grande mine, Chile.

Beschreibung: Matulaite was first described by Moore and Ito (1980) from the Bachman mine, Hellertown, Northampton County, Pennsylvania, USA. Its ideal formula was reported as CaAl18(PO4)12(OH)20·28H2O, based on wet-chemical analysis. Re-examination of both existing cotype specimens of matulaite revealed no material matching the powder or single-crystal X-ray diffraction data reported for the species. Other samples examined from the type locality, as well as from the LCA pegmatite in North Carolina, USA, and Fumade, Tarn, France, provided material crystallographically consistent with matulaite: P21/n, a = 10.604(2), b = 16.608(4), c = 20.647(5) Å, β = 98.848(7)° and Z = 4. Electron microprobe and crystal structure analysis of newly studied material from the type locality showed the ideal formula of matulaite to be Fe3+Al7(PO4)4(PO3OH)2(OH)8(H2O)8·8H2O. The chemical composition reported by Moore and Ito (1980) was most probably determined on a mixture of mostly kobokoboite and afmite, with lesser amounts of crandallite. As there is no matulaite on any of the existing cotype specimens of the species, the two specimens used to obtain the new chemical analyses, powder and single-crystal X-ray diffraction data and the structure determination are designated as neotypes. The neotypes have also been used to obtain crystal morphology and new measurements of the physical and optical properties of the species. The neotypes and new data have been approved by the CNMNC, proposal 11-F. The crystal structure of matulaite contains seven-member chain segments of AlO6 octahedra decorated by PO4 tetrahedra. The PO4 tetrahedra also link to isolated FeO6 octahedra, resulting in a ‘pinwheel’ Fe(PO4)6 group. The linkage of octahedra and tetrahedra defines a thick layer parallel to {001}. The only linkage between layers is via hydrogen bonding to interlayer water molecules.

Beschreibung: New data for parnauite from the type locality, Majuba Hill, Nevada, USA (MH; type specimen), and also from Cap Garonne, Var, France (CG), and the Clara Mine, Baden-Württemberg, Germany, are presented. The average chemical composition of MH material is (Cu 8.82 Al 0.16 Fe 0.02 ) 9.00 (As 1.78 Al 0.07 Si 0.08 S 0.07 ) 2.00 O 8 (SO 4 )(OH) 10 ·7H 2 O and that of CG parnauite, (Cu 8.42 Al 0.21 Zn 0.10 ) 8.73 (AsO 4 ) 2 [(S 0.97 As 0.10 ) 1.07 O 4 ](OH 9.23 Cl 0.77 ) 10.00 · 7H 2 O. Both of these formulae confirm the 9:2:1 Cu:As:S ratio obtained from earlier descriptions of parnauite. Raman spectra for parnauite from both localities are very similar. Bands are assigned, but show no evidence of the presence of CO 3 , in contrast to previous studies, and no distinct Cu–Cl stretching mode. It appears that neither the minor CO 3 and PO 4 previously reported nor Cl are essential constituents of parnauite. Single-crystal XRD analysis indicates a primitive orthorhombic unit cell with dimensions 6 x 14 x 15 Å, similar to previous studies, but h = odd reflections were heavily streaked and diffuse, preventing full refinement. A 3 Å substructure was refined, with space group Pmn 2 1 , to R 1 ( F ) = 0.0750 (MH). For a MH crystal, the subcell had a = 3.0113(4), b = 14.259(3), c = 14.932(2) Å, V = 641.13(16) Å 3 and Z = 1. The structure is of a new type, and contains Cu in 6 distinct sites, forming two three-polyhedron wide ribbons of edge-sharing Cu-O polyhedra extended parallel to the a - axis. The two ribbons lie back-to-back and are bridged by two AsO 4 tetrahedra. The collection of 6Cu + 2As cations plus ligands forms a rod-like moiety extended || a . These rods link through polyhedral corners to form complex, corrugated (010) layers. The interlayer space is occupied by H 2 O molecules. Thus, the disorder observed by XRD is of an unusual type, in which the shape of the unit mesh within layers is variable, rather than the stacking of the layers. Disorder arises because each AsO 4 tetrahedron shares a face with a Cu(O,OH,H 2 O) 5–6 polyhedron in the substructure, necessitating partial occupancy of both As and Cu sites. The S atoms were not located in the refinement, but four electron-density maxima in the interlayer region were interpreted as H 2 O molecules. Hence, the simplified structural formula derived from the substructure is (Cu 10 2 )(As 2 2 )O 8 (OH) 14 ·8H 2 O, deviating from that obtained in chemical analyses. The discrepancy presumably arises due to strong delocalisation of the sulphur and the apical oxygen of the SO 4 tetrahedron in the substructure. Short-range order of Cu–As and Cu–S || a can occur independently in the relevant structural rods, which accounts for the observed long-range disorder. Cell parameters and substructures obtained from CG and Clara material are similar to those from the MH crystal. Site splitting of OH positions in the CG refinement indicates that Cl is distributed over several sites in the 3 Å substructure, making the mineral a Cl-rich variety of parnauite rather than a distinct mineral species.

Beschreibung: Bariopharmacoalumite- Q 2 a 2 b 2 c , Ba 0.5 (Cu,ZnO) 0.1 H 0.6 [Al 4 (OH) 4 (As 0.9 Al 0.1 O 4 ) 3 ]·5.5H 2 O, from the south mine of the old copper mine at Cap Garonne, France, has a 2 x 2 x 2 I -centred tetragonal superstructure of the basic pharmacosiderite-type structure. Cell parameters are a = 15.405(2) Å and c = 15.553(3) Å. The structure was determined and refined in I 4I2 m to R 1 = 0.057 for 2697 reflections with I 〉 2( I ), using synchrotron X-ray data on a twinned crystal. The origin of the superlattice cell doubling was determined to be due predominantly to the ordering of Ba atoms in half of the [0 0 1] channels, centred at (0, 0, 0) and (1/2, 1/2, 0). The other channels, centred at (1/2, 0, 0) and (0, 1/2, 0), were found to be occupied by corner-connected chains of Cu/Zn-centred square planar units.

Beschreibung: We present Raman data for camerolaite, cyanotrichite and carbonatecyanotrichite, and using synchrotron single-crystal X-ray diffraction have solved the structure of camerolaite from the Tistoulet Mine, Padern, Aude Department, France. Camerolaite crystallizes in space group P 1 with the unit-cell parameters: a = 6.3310(13) Å, b = 2.9130(6) Å, c = 10.727(2) Å, α = 93.77(3)°, β = 96.34(3)°, = 79.03(3)°, V = 192.82(7) Å 3 and Z = 1/3, with respect to the ideal formula from the refinement, Cu 6 Al 3 (OH) 18 (H 2 O) 2 [Sb(OH) 6 ](SO 4 ). The crystal structure was solved to R 1 = 0.0890 for all 1875 observed reflections [ F o 〉 4 F o ] and 0.0946 for all 2019 unique reflections. The P cell has been transformed into a C -centred cell that aids comparison with that of the structurally related khaidarkanite by a C = 2 a P – b P , giving parameters a = 12.441(3), b = 2.9130(6), c = 10.727(2) Å, α = 93.77(3), β = 95.57(3), = 92.32(3)° and Z = 2/3 in C 1. Edge-sharing octahedral ribbons Cu 2 Al(O,OH,H 2 O) 8 form hydrogen-bonded layers || (001), as in khaidarkanite. The partially occupied interlayer Sb and S sites of the average structure are in octahedral and tetrahedral coordination by oxygen, respectively. They cannot be occupied simultaneously, which leads to regular alternation of [Sb(OH) 6 ] – and $${\mathrm{SO}}_{4}^{2-}$$ groups in rods || y , resulting in local tripling of the periodicity along y for the Sb(OH) 6 –SO 4 rods. Thus, camerolaite has a ‘host–guest’ structure in which an invariant host module (layers of Cu–Al ribbons) has embedded rod-like guest modules with a longer periodicity. Coupling between the phases of these rods is only short-range, resulting in diffuse X-ray scattering rather than sharp superstructure reflections. Similar disorder is known for parnauite, and is deduced for other members of the cyanotrichite group (cyanotrichite, carbonatecyanotrichite and khaidarkanite). Group members all share the Cu–Al ribbon module but have interlayer rods of different compositions and topologies; thus, they form a merotypic family. The low symmetry of the camerolaite average structure suggests other possibilities for structure variation in the group, which are discussed.

Beschreibung: Zincalstibite-9R, a new polytype in the hydrotalcite supergroup is reported from the Monte Avanza mine, Italy. It occurs as pale blue curved disc-like tablets flattened on {001} intergrown to form rosettes typically less than 50 μm in diameter, with cyanophyllite and linarite in cavities in baryte. Zincalstibite-9R is uniaxial (−), with refractive indices ω = 1.647(2) and ε = 1.626(2) measured in white light. The empirical formula (based on 12 OH groups) is ( Al0.04)Σ2.00Al1.01 ( Si0.02)Σ0.99(OH)12, and the ideal formula is (Zn,Cu)2Al(OH)6[Sb(OH)6]. Zincalstibite-9R crystallizes in space group R3İ, with a = 5.340(2), c = 88.01(2) Å, V = 2173.70(15) Å3 and Z = 9. The crystal structure was refined to R1 = 0.0931 for 370 unique reflections [Fo 〉 4σ(F)] and R1 = 0.0944 for all 381 unique reflections. It has the longest periodic layer stacking sequence for a layered double hydroxide compound reported to date.

Beschreibung: Angarfite, ideally NaFe 3+ 5 (PO 4 ) 4 (OH) 4 ·4H 2 O, is a new mineral from the Angarf-Sud pegmatite, Tazenakht, Ouarzazate Province, Souss-Massa-Draâ region, Morocco. The mineral occurs on etched surfaces of triphylite in association with lipscombite–barbosalite, jahnsite-(NaFeMg) and bederite. It is interpreted as having resulted from the reaction of Na-bearing hydrothermal solutions with primary triphylite. The crystals are orange-brown to red-brown needles and prisms, elongate on [001], with poorly formed chisel-like terminations. The mineral is transparent and has a pale brown streak, a vitreous luster, a Mohs hardness of approximately 21/2, a splintery fracture and one poorly developed cleavage on {010}. It is brittle, but thin needles are slightly flexible. The measured and calculated densities are 2.76(3) and 2.771 g/cm 3 , respectively. It is optically biaxial (+),α 1.688(1), β 1.696(1), 1.708(2) (white light); 2 V meas = 80(3)°; 2 V calc = 79°; strong r 〉 v dispersion; optical orientation: X = b , Y = c , Z = a ; pleochroism: X is tan, Y , medium red-brown, and Z , dark red-brown, with X 〈 Y 〈 Z . The average results of five electron-microprobe analyses gave Na 2 O 2.69, MgO 4.76, Mn 2 O 3 1.79, Fe 2 O 3 37.36, P 2 O 5 34.68, H 2 O 14.63 (from structure refinement), total 95.91 wt%. The empirical formula, based on 24 O atoms, is Na 0.71 (Fe 3+ 3.83 Mg 0.97 Mn 3+ 0.19 ) 4.99 (P 1.00 O 4 ) 4 (OH) 2.71 (H 2 O) 1.29 ·4H 2 O. Angarfite is orthorhombic, C 222 1 , a 12.7997(3), b 17.9081(4), c 8.2112(6) Å, V 1882.16(15) Å 3 and Z = 4. The eight strongest lines in the X-ray powder-diffraction pattern [ d obs in Å( I )( hkl )] are: 10.463(43)(110), 9.016(100)(020), 6.459(42)(111), 3.731(27)(022), 3.355(51)(241), 3.026(29)(042), 1.926(33)(462, 263), 1.463(36)(822, 663, 4 10 2, 2 10 3). The crystal structure ( R 1 = 3.02% for 2074 reflections, F o 〉 4 F ) contains zig-zag chains of edge-sharing Fe 3+ O 6 octahedra along c , which are linked into sheets parallel to {010} by sharing corners with octahedra in adjacent chains and by sharing corners with peripheral PO 4 tetrahedra. Insular octahedra between the sheets share two sets of cis corners with tetrahedra in adjacent sheets, thereby linking the sheets into a framework. Channels in the framework parallel to c contain a partially occupied Na site and a disordered H 2 O site. Identical sheets of octahedra and tetrahedra are found in the structures of bakhchisaraitsevite and mejillonesite.

Beschreibung: The thallium-rich sulfosalt deposit of Jas Roux, situated in the Pelvoux Massif (Hautes-Alpes département , France), occurs in a Triassic sedimentary series. Jasrouxite belongs to the early lead-containing stages of the Tl–As–Sb period of mineralization. It occurs in a silicified gangue, along with smithite and late realgar. Jarouxite forms dark gray anhedral grains with metallic luster, up to several millimeters in size, as well as aggregates of grains which range to more than 10 mm in diameter. From their surface, grains of jasrouxite are embayed by a three-phase myrmekite aggregate composed of stibnite, boscardinite and smithite. The mineral is brittle, with irregular fracture; no cleavage or parting was observed. In reflected light, color is off-white. Bireflectance is weak, in off-white tones; anisotropy is distinct. Rare straight twin lamellae occur in otherwise untwinned crystals. The empirical formula, on the basis of 132 apfu derived from the crystal-structure determination, is Cu 0.79 Ag 14.64 Pb 4.10 T l0.05 As 15.37 Sb 24.87 S 72.18 . Calculated density is 4.87 g.cm –3 . The simplified formula is Ag 16 Pb 4 (Sb 25 As 15 ) 40 S 72 ; the only notable variation is the partial substitution AsSb. Jasrouxite is triclinic, space group P -1. Lattice parameters are a 8.2917(5) Å, b 19.101(1) Å, c 19.487(1) Å, α 89.731(1)°, β 83.446(1)°, 89.944(1)°, V 3066.1(3) Å 3 , Z= 1 for Ag 16 Pb 4 (Sb 24 As 16 ) 40 S 72 . Jasrouxite is a member of the lillianite homologous series, its order number is 4 and degree of Ag + (Sb, As) 2 Pb substitution is 36.5 % above the theoretical 100 % substitution expressed as PbAg(Sb,As) 3 S 6 . The most important features of the crystal structure are: substantial replacement of lead in selected trigonal prismatic sites by Sb, formation of a string of large volumes for accommodation of lone electrons of Sb and As in the central portions of galena-like slabs, and high contents of Ag and (Sb,As).

Beschreibung: Alfredopetrovite, Al 2 (Se 4+ O 3 ) 3 · 6H 2 O, is a new secondary selenite mineral from the El Dragón mine, Antonio Quijarro Province, Potosí Department, Bolivia. The mineral occurs in vugs in a matrix of Co-rich krut’aite–penroseite, dolomite and goethite. Associated minerals are: ahlfeldite, allophane, calcite, chalcomenite, favreauite, felsőbányaite, malachite and molybdomenite. Crystals occur in drusy/scaly coatings and compact balls, the latter to 0.5 mm in diameter. Individual crystals are up to about 0.1 mm across. The Mohs hardness of alfredopetrovite is 21/2; it has no cleavage, curved fracture and a vitreous lustre. The calculated density based on the empirical formula is 2.504 g cm –3 . Alfredopetrovite is uniaxial (+), with = 1.554(2) and = 1.566(2) (white light), and exhibits no pleochroism. Electron microprobe analyses gave the empirical formula Al 1.94 Cu 0.07 Ni 0.03 Co 0.01 Se 2.95 O 15 H12.16, based on 15 O apfu . Alfredopetrovite is hexagonal, space group P $$\overline{6}$$ 2 c , with the unit-cell parameters: a = 8.818(3) Å, c = 10.721(2) Å, V = 722.0(5) Å 3 and Z = 2. The eight strongest lines in the X-ray powder diffraction pattern are [ d obs /Å ( I ) ( hkl )]: 7.63(55)(100), 6.22(55)(101), 5.37(26)(002), 4.398(40)(110,102), 3.404(100)(112), 2.783(50)(211), 2.606(22)(203), and 1.6609(26)(410,322,314,116). The crystal structure was refined to R 1 = 0.0268 for 240 observed reflections [ F o 〉 4 F ]. The structure is comprised of fairly regular AlO 6 octahedra and Se 4+ O 3 triangular pyramids. Three Se 4+ O 3 pyramids link two adjacent AlO 6 octahedra forming a [Al(H 2 O) 3 | 2 (Se 4+ O 3 ) 3 cluster structural unit. These structural units are bonded to one another only via hydrogen bonds yielding a structure with relatively large channels along [001]. The configuration of the cluster is similar to that of the distinctive unit in the NASICON structure, commonly referred to as a lantern unit .

Beschreibung: Omsite (IMA 2012-025) is a new mineral from the Correc d'en Llinassos, Oms, Pyrénées-Orientales Department, France. It occurs as bright yellow to amber yellow discoidal tablets, flattened on {001}, which form rosettes typically 50–100 μm in diameter. Omsite generally crystallizes on siderite without associated supergene minerals; it occurs less commonly with glaukosphaerite. Crystals have a vitreous to resinous lustre, and are transparent to translucent. Omsite is not fluorescent in either short-wave or long-wave ultraviolet light. It has an estimated hardness of 3 on the Mohs' scale, is brittle with an irregular fracture, and has one poor cleavage on {001}. The calculated density is 3.378 g cm−3. Crystals are uniaxial (−), with indices of refraction of ω = 1.728(3) and ε = 1.66(1), measured in white light. Pleochroism is ω = orange-yellow, ε = pale orange-yellow; ω 〉 ε. The empirical formula [based on 12 (OH + Cl) p.f.u.] is ( Mg0.107 )Σ1.916 ( As0.072Na0.029)Σ1.048OH11.967Cl0.033. Omsite crystallizes in space group P3İ, with unit-cell parameters a = 5.3506(8), c = 19.5802(15) Å, V = 485.46(10) Å3 and Z = 2 determined by single crystal X-ray diffraction. The five strongest lines in the X-ray powder diffraction pattern [d in Å, (Irel), (hkl)] are as follows: 4.901, (100), (004); 4.575, (83), (011); 2.3539, (81), (114İ); 1.8079, (48), (118İ); 3.781, (34), (103). The crystal structure was solved to R1 = 0.0896 for 356 observed reflections [Fo〉4σFo] and 0.1018 for all the 469 unique reflections. Omsite is a layered double hydroxide (LDH) mineral, with a topology consistent with members of the hydrotalcite supergroup and cualstibite group.