From ancient pigments to modern optoelectronic applications of arsenic sulfides: bonazziite, the natural analogue of β-As4S4 from Khaidarkan deposit, Kyrgyzstan

2015 ◽  
Vol 79 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Luca Bindi ◽  
Giovanni Pratesi ◽  
Maurizio Muniz-Miranda ◽  
Matteo Zoppi ◽  
Laura Chelazzi ◽  
...  
Keyword(s):  
Incident Light ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
Thick Section ◽  
Natural Analogue ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Dark Orange ◽  
Mohs Hardness ◽  
Arsenic Sulfides

AbstractBonazziite is a new mineral from Khaidarkan deposit, Kyrgyzstan and represents the natural analogue of the β-form of the well known As4S4 compound. It occurs as rare crystals up to 100 μm across associated with realgar, sulfur, wakabayashilite, alacránite, non-stoichiometric As4S4+x sulfides and stibnite in a calcite matrix. In thick section, bonazziite is opaque with a resinous lustre and a dark-orange streak. It is brittle; the Vickers hardness (VHN15) is 70 kg/mm2 (range: 60–76) (Mohs hardness of ∼2½). In plane-polarized incident light, bonazziite is strongly bireflectant and pleochroic from orange to light red. The mineral shows orange to red internal reflections. Between crossed polars, the mineral is strongly anisotropic with greyish to light-blue rotation tints. Reflectance percentages in air for Rmin and Rmax are 19.9, 22.2 (471.1 nm), 19.1, 21.3 (548.3 nm), 18.8, 19.7 (586.6 nm) and 17.8, 18.9 (652.3 nm), respectively. Bonazziite is monoclinic, space group C2/c, with a = 9.956(1), b = 9.308(1), c = 8.869(1) Å, β = 102.55(2)° and V = 802.3(2) Å3, Z = 4. The crystal structure [R1 = 0.0263 for 735 reflections with Fo > 4σ(Fo)] is based on the As4S4 cage-like molecule, in which each As atom links one As and two S atoms. The As4S4 molecule is identical to that found in the structure of realgar. The six strongest powder diffraction lines [d in Å (I/I0) (hkl)] are: 5.74 (100) (1̄11); 4.10 (60) (021); 3.92 (50) (1̄12); 3.12 (60) (022, 310); 2.95 (50) (221, 202); 2.86 (80) (2̄22, 1̄31). a mean of six electron microprobe analyses gave the formula As3.95S4.05, on the basis of eight atoms. The new mineral has been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA No. 2013-141) and named for Paola Bonazzi, in recognition of her seminal contributions to the study of arsenic sulfides and their alteration induced by exposure to light.

Tl-bearing sulfosalt from the Lengenbach quarry, Binn Valley, Switzerland: Philrothite, TlAs3S5

2014 ◽  
Vol 78 (1) ◽  
pp. 1-9 ◽  
Author(s):  
L. Bindi ◽  
F. Nestola ◽  
E. Makovicky ◽  
A. Guastoni ◽  
L. De Battisti
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Double Layers ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
Electron Pairs ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Reflected Light ◽  
Mohs Hardness

AbstractPhilrothite, ideally TlAs3S5, is a new mineral from the Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs as very rare crystals up to 200 mm across on realgar associated with smithite, rutile and sartorite. Philrothite is opaque with a metallic lustre and shows a dark brown streak. It is brittle; the Vickers hardness (VHN25) is 128 kg/mm2 (range: 120–137) (Mohs hardness of 3–3½). In reflected light philrothite is moderately bireflectant and weakly pleochroic from dark grey to light grey. Under crossed polars it is anisotropic with grey to bluish rotation tints. Internal reflections are absent. Reflectance percentages for the four COM wavelengths (Rmin and Rmax) are: 26.5, 28.8 (471.1 nm), 25.4, 27.2 (548.3 nm), 24.6, 26.3 (586.6 nm) and 24.0, 25.1 (652.3 nm), respectively.Philrothite is monoclinic, space group P21/c, with a = 8.013(2), b = 24.829(4), c = 11.762(3) Å, β = 132.84(2)°, V = 1715.9(7) Å3, Z = 8. It represents the N = 4 homologue of the sartorite homologous series. In the crystal structure [R1 = 0.098 for 1217 reflections with I > 2σ(I)], Tl assumes tricapped prismatic sites alternating to form columns perpendicular to the b axis. Between the zigzag walls of Tl coordination prisms, coordination pyramids of As(Sb) form diagonally-oriented double layers separated by broader interspaces which house the lone electron pairs of these elements.The eight strongest calculated powder-diffraction lines [d in Å(I/I0) (hkl)] are: 12.4145 (52) (020); 3.6768 (100) (61); 3.4535 (45) (131); 3.0150 (46) (53); 2.8941 (52) (81); 2.7685 (76) (230); 2.7642 (77) (34); 2.3239 (52) (092). A mean of five electron microprobe analyses gave Tl 26.28(12), Pb 6.69(8), Ag 2.50(4), Cu 0.04(2), Hg 0.07(2), As 32.50(13), Sb 3.15(3), S 26.35(10), total 97.58 wt.%, corresponding, on the basis of a total of nine atoms, to (Tl0.789Pb0.198)∑=0.987 (As2.662Sb0.159Ag0.142Cu0.004Hg0.002)∑=2.969S5.044. The new mineral has been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association (2013-066) and named for Philippe Roth (b. 1963), geophysicist and well known mineral expert on the Lengenbach minerals for more than 25 years.

Eckerite, Ag2CuAsS3, a new Cu-bearing sulfosalt from Lengenbach quarry, Binn valley, Switzerland: description and crystal structure

2015 ◽  
Vol 79 (3) ◽  
pp. 687-694 ◽  
Author(s):  
L. Bindi ◽  
F. Nestola ◽  
S. Graeser ◽  
P. Tropper ◽  
T. Raber
Keyword(s):  
Crystal Structure ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
International Mineralogical Association ◽  
Cu Substitution ◽  
Reflected Light ◽  
Dark Orange ◽  
Mohs Hardness ◽  
The Mean

AbstractEckerite, ideally Ag2CuAsS3, is a new mineral from the Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs as very rare euhedral crystals up to 300 μm across associated with realgar, sinnerite, hatchite, trechmannite and yellow, fibrous smithite. In thick section eckerite is opaque with a metallic lustre and shows a dark orange-red streak. It is brittle; the Vickers hardness (VHN25) is 70 kg/mm2 (range: 64–78) (Mohs hardness of ∼2½–3). In reflected light, eckerite is moderately bireflectant and weakly pleochroic from light grey to a slightly bluish grey. Internal reflections are absent. Under crossed nicols, it is weakly anisotropic with greyish to light blue rotation tints. Reflectance percentages for Rmin and Rmax are 27.6, 31.7 (471.1 nm), 22.8, 26.1 (548.3 nm), 21.5, 24.5 (586.6 nm) and 19.4, 22.3 (652.3 nm), respectively.Eckerite is monoclinic, space group C2/c, with a = 11.8643(3), b = 6.2338(1), c = 16.6785(4) Å, β = 110.842(3)°, V = 1152.81(5) Å3, Z = 8. The crystal structure [R1 = 0.0769 for 1606 reflections with Fo > 4σ(Fo)] is topologically identical to that of xanthoconite and pyrostilpnite. In the structure, AsS3 pyramids are joined by AgS3 triangles to form double sheets parallel to (001); the sheets are linked by Cu(Ag) atoms in a quasi-tetrahedral coordination. Among the three metals sites, Ag2 is dominated by Cu. The mean metal–S distances reflect well the Ag ↔ Cu substitution occurring at this site.The eight strongest powder X-ray diffraction lines [d in Å (I/I0) (hkl)] are: 3.336 (70) (312); 2.941 (100) (314,114); 2.776 (80) (400,206); 2.677 (40) (312); 2.134 (50) (421); 2.084 (40) (208,206); 2.076 (40) (420); 1.738 (40) (228,226). A mean of five electron microprobe analyses gave Ag 52.08(16), Cu 11.18(9), Pb 0.04(1), Sb 0.29(3), As 15.28(11), S 20.73(13), total 99.60 wt.%, corresponding, on the basis of a total of 7 atoms per formula unit, to Ag2.24Cu0.82As0.94Sb0.01S2.99. The new mineral has been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (2014–063) and named for Markus Ecker, a well known mineral expert on the Lengenbach minerals for more than 25 years.

Mesaite, (V2O7)3·12H2O, a new vanadate mineral from the Packrat mine, near Gateway, Mesa County, Colorado, USA

2017 ◽  
Vol 81 (2) ◽  
pp. 319-327 ◽  
Author(s):  
Anthony R. Kampf ◽  
Barbara P. Nash ◽  
Joe Marty ◽  
John M. Hughes
Keyword(s):  
Powder Diffraction ◽  
New Mineral ◽  
Formula Unit ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Interlayer Region ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
Measured Density

AbstractMesaite (IMA2015-069), ideally (V2O7)3·12H2O, is a new mineral from the Packrat mine, Gateway district, Mesa County, Colorado, USA. Crystals of mesaite occur as orangish red blades up to 0.1 mm long and ∼10 μm thick. The streak is light pinkish orange and the lustre is vitreous, transparent. Mesaite has a brittle tenacity, {010} perfect cleavage; fracture is irregular, and no parting was observed. The mineral has a Mohs hardness ≈ 2. The measured density of mesaite is 2.74(1) g cm–3. Mesaite is biaxial (–), α = 1.760(calc), β = 1.780(5), γ = 1.795(5) in white light; the measured 2V value = 81(2)°. Dispersion is strong, r < v, and pleochroism is present in shades of brownish orange. Mesaite is monoclinic, P2/n, with a = 9.146(2), b = 10.424(3), c = 15.532(4) Å, β = 102.653(7)° and V = 1444.7(6) Å3. The strongest four diffraction lines in the powder diffraction pattern are [(dobs in Å, (Iobs), (hkl)]: 10.47 (100) (010), 2.881 (25) (132, 3̄12, 033, 310), 3.568 (24) (1̄14, 1̄23, 2̄13), 3.067 (17) (1̄24, 1̄32, 2̄23). The composition of mesaite was determined by electron microprobe, and yielded an empirical formula of Mn5.32Ca0.56Zn0.31V5.96As0.04O33H23.61 on the basis of 33 O atoms per formula unit (apfu).The atomic arrangement of mesaite was solved and refined to R1 = 0.0600. The structure is formed of zigzag octahedral chains of edge-sharing Mn2+O6 octahedra. Oxygen atoms of the octahedra are shared with V2O7 groups, which link with adjacent octahedral chains to form {010} heteropolyhedral layers. The interlayer region contains Ca atoms and H2O groups. Each Ca bonds to two O6 atoms in the heteropolyhedral layer and to two fully occupied and six partially occupied O (H2O) sites in the interlayer, resulting in an effective Ca coordination of approximately seven. Similar zigzag chains of edge-sharing MnO6 octahedra decorated with V2O7 groups are also found in the mineral fianelite. Mesaite has beenapproved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-069). The name mesaite is conferred for Mesa County, Colorado, USA.

scholarly journals Hansblockite, (Cu,Hg)(Bi,Pb)Se2, the monoclinic polymorph of grundmannite: a new mineral from the Se mineralization at El Dragón (Bolivia)

2017 ◽  
Vol 81 (3) ◽  
pp. 629-640 ◽  
Author(s):  
Hans-Jürgen Förster ◽  
Luca Bindi ◽  
Chris J. Stanley ◽  
Günter Grundmann
Keyword(s):  
Incident Light ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coupled Substitution ◽  
Mohs Hardness ◽  
Ore Mineralogy ◽  
The Mean

AbstractHansblockite, ideally (Cu,Hg)(Bi,Pb)Se2, is a new selenide from the El Dragón mine, Bolivia. It typically occurs in thin subparallel plates intergrown with two unnamed Cu–Hg–Pb–Bi–Se species, clausthalite, Corich penroseite and petrovicite.It also forms subhedral to anhedral grains up to 150 μm long and 50 μm wide. Hansblockite is non-fluorescent, black and opaque with a metallic lustre and black streak. It is brittle, with an irregular fracture and no obvious parting and cleavage. The VHN20 values range from37 to 50 (mean 42) kg mm–2 (Mohs hardness 2–2½). In plane-polarized incident light, hansblockite is cream to light grey in colour, weakly bireflectant and weakly pleochroic from greyish cream to cream. Under crossed polars, hansblockite is weakly anisotropic withkhaki to pale blue rotation tints. The reflectance values in air for the Commission on Ore Mineralogy (COM) standard wavelengths are: 47.3–48.1 (470 nm), 47.4–49.9 (546 nm), 47.1–49.0 (589 nm) and 46.6–48.5 (650 nm). The mean composition is Cu 9.31, Ag 0.73, Hg 11.43,Pb 3.55, Ni 0.17, Co 0.03, Bi 31.17, Se 34.00, total 100.39 wt.%. The mean empirical formula (based on 4 apfu) is (Cu0.68Hg0.27Ag0.03Ni0.01)∑=0.99(Bi0.69Pb0.31)∑=1.00Se2.01. The simplifiedformula is (Cu,Hg) (Bi,Pb)Se2. Hansblockite is monoclinic, space group P21/c, with a = 6.853(1), b = 7.635(1), c = 7.264(1) Å, β = 97.68(1)°, V = 376.66(9) Å3 and Z = 4. Density is 8.26 gcm–3. The five strongest powder X-ray diffraction lines [d in Å (I/I0) (hkl)] are: 3.97 (90) (111), 3.100 (40) (121), 2.986 (100) (211), 2.808 (50) (112) and 2.620 (50) (022). Hansblockite represents the monoclinic polymorph ofgrundmannite, CuBiSe2, with Hg and Pb being essential in stabilizing the monoclinic structure via the coupled substitution Cu+ + Bi3+⇔ Hg2+ + Pb2+. The mineral name is in honour of Hans Block (1881–1953), in recognition of hisimportant role in boosting Bolivian ore mining.

Eleonorite, Fe63+(PO4)4O(OH)4·6H2O: validation as a mineral species and new data

2017 ◽  
Vol 81 (1) ◽  
pp. 61-76 ◽  
Author(s):  
Nikita V. Chukanov ◽  
Sergey M. Aksenov ◽  
Ramiza K. Rastsvetaeva ◽  
Christof Schäfer ◽  
Igor V. Pekov ◽  
...  
Keyword(s):  
Mineral Species ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Iron Mine ◽  
Mohs Hardness ◽  
Heteropolyhedral Framework ◽  
Mössbauer Analysis

AbstractEleonorite, ideally Fe63+(PO4)4O(OH)4·6H2O, the analogue of beraunite Fe2+Fe53+(PO4)4O(OH)5·6H2O with Fe2+ completely substituted by Fe3+, has been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification as a mineral species (IMA 2015-003). The mineral was first described on material from the Eleonore Iron mine, Dünsberg, near Giessen, Hesse, Germany, but during this study further samples were required and a neotype locality is the Rotläufchen mine, Waldgirmes, Wetzlar, Hesse, Germany, where eleonorite is associated with goethite, rockbridgeite, dufrénite, kidwellite, variscite, matulaite, planerite, cacoxenite, strengite and wavellite. Usually eleonorite occurs as red-brown prismatic crystals up to 0.2 mm × 0.5 mm × 3.5 mm in size and in random or radial aggregates up to 5 mm across encrusting cavities in massive 'limonite'. The mineral is brittle. Its Mohs hardness is 3. Dmeas = 2.92(1), Dcalc = 2.931 g cm–3. The IR spectrum is given. Eleonorite is optically biaxial (+), α = 1.765(4), β = 1.780(5), γ = 1.812(6), 2Vmeas = 75(10)°, 2Vcalc = 70°. The chemical composition (electron microprobe data, H2O analysed by chromatography of products of ignition at 1200°C, wt.%) is: Al2O3 1.03, Mn2O3 0.82, Fe2O3 51.34, P2O5 31.06, H2O 16.4, total 99.58. All iron was determined as being trivalent from a Mössbauer analysis. The empirical formula (based on 27 O apfu) is (Fe5.763+Al0.18Mn0.093+)∑6.03(PO4)3.92O(OH)4.34·5.98H2O. The crystal structure (R = 0.0633) is similar to that of beraunite and is based on a heteropolyhedral framework formed by M(1–4)Ø6-octahedra (where M = Fe3+; Ø = O2–, OH– or H2O) and isolated PO4 tetrahedra, with a wide channel occupied by H2O molecules. Eleonorite is monoclinic, space group C2/c, a = 20.679(10), b = 5.148(2), c = 19.223(9) Å, β = 93.574(9)°, V = 2042.5(16) Å3 and Z = 4. The strongest reflections of the powder X-ray diffraction pattern [d, Å (I,%) (Hkl)] are 10.41 (100) (200), 9.67 (38) (002), 7.30 (29) (202̄), 4.816 (31) (111, 004), 3.432 (18) (600, 114, 404, 313), 3.197 (18) (510, 511̄, 006, 314̄, 602), 3.071 (34) (314, 115̄).

Cámaraite, Ba3NaTi4(Fe2+,Mn)8(Si2O7)4O4(OH,F)7. I. A new Ti-silicate mineral from the Verkhnee Espe Deposit, Akjailyautas Mountains, Kazakhstan

2009 ◽  
Vol 73 (5) ◽  
pp. 847-854 ◽  
Author(s):  
E. Sokolova ◽  
Y. Abdu ◽  
F. C. Hawthorne ◽  
A. V. Stepanov ◽  
G. K. Bekenova ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Refractive Indices ◽  
New Mineral ◽  
Silicate Mineral ◽  
Calculated Density ◽  
Triclinic Space Group ◽  
X Ray ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Mohs Hardness

AbstractCámaraite, ideally Ba3NaTi4(Fe2+,Mn)8(Si2O7)4O4(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 mm × 15 mm × 2 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-3. In transmitted light, camaraite is strongly pleochroic, X = light brown, Y = reddish-brown, Z = yellow- brown, with Z < X < Y. Cámaraite is biaxial +ve and 2Vmeas. = 93(1)°. All refractive indices are greater than 1.80. Cámaraite is triclinic, space group C, a = 10.678(4) Å, b = 13.744(8) Å, c = 21.40(2) Å, α = 99.28(8)°, β = 92.38(5)°, γ = 90.00(6)°, V = 3096(3) Å3, 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 (Å), (I), (hkl)]: 2.63, (100), (401); 2.79, (90), (3, 41, 26, 225); 1.721, (70), (11, 49, 02); 3.39, (50), (24, 223); 3.18, (50), (5, 24); 2.101, (50), (2, 40); 1.578, (50), (1, 2, 61, 40). Chemical analysis by electron microprobe gave: Nb2O5 1.57, SiO2 25.25, TiO2 15.69, ZrO2 0.33, Al2O3 0.13, Fe2O3 2.77, FeO 16.54, MnO 9.46, ZnO 0.12, MgO 0.21, CaO 0.56, BaO 21.11, Na2O 1.41, K2O 0.84, H2O 1.84, F 3.11, less O:F 1.31, total 99.63 wt.%, where the valence state of Fe was determined by Mössbauer spectroscopy [Fe3+/(Fe2+ + Fe3+) = 0.13(8)] and the H2O content was derived by crystal-structure determination. The resulting empirical formula on the basis of 39 anions is Ca0.05)Σ7.78Si7.97O35.89H3.88F3.11. Cámaraite is a Group-II TS-block mineral in the structure hierarchy of Sokolova (2006). The mineral is named camaraite after Fernando Cámaraite (born 1967) of Melilla, Spain, in recognition of his contribution to the fields of mineralogy and crystallography. The new mineral and mineral name have been approved by the Commission on New Minerals, Nomenclature and Classification, International Mineralogical Association (IMA 2009-11).

scholarly journals Biagioniite, Tl2SbS2, from the Hemlo gold deposit, Marathon, Ontario, Canada: occurrence and crystal structure

2020 ◽  
Vol 84 (3) ◽  
pp. 390-397 ◽  
Author(s):  
Luca Bindi ◽  
Yves Moëlo
Keyword(s):  
Crystal Structure ◽  
Gold Deposit ◽  
Native Gold ◽  
Associate Professor ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
International Mineralogical Association ◽  
Mineralogical Association ◽  
Reflected Light ◽  
The University

AbstractBiagioniite, ideally Tl2SbS2, is a new mineral from the Hemlo gold deposit, Marathon, Ontario, Canada. It occurs as very rare anhedral crystals up to 65 μm across associated with aurostibite, stibarsen and native gold in a calcite matrix. Biagioniite is opaque with a metallic lustre and shows a black streak. In reflected light biagioniite is moderately bireflectant and not pleochroic. Under crossed polars it is weakly anisotropic with blueish to light-blue rotation tints. Internal reflections are absent.Reflectance percentages for the four standard wavelengths (Rmin and Rmax) are 35.9 and 37.5 (471.1 nm); 34.7 and 36.2 (548.3 nm); 33.8 and 35.3 (586.6 nm); and 31.5 and 33.7 (652.3 nm), respectively. A mean of four electron microprobe analyses gave: Tl 65.12(31), Ag 3.52(9), Sb 20.22(12), S 10.80(8), total 99.66 wt.%, corresponding, on the basis of a total of 5 atoms, to (Tl1.87Ag0.19)Σ2.06Sb0.97S1.97. Biagioniite is monoclinic, space group Pc, with a = 11.0895(9), b = 14.3124(11), c = 7.9352(6) Å, β = 96.230(8)°, V = 1252.02(17) Å3 and Z = 8. The four strongest powder-diffraction lines [d in Å (I/I0) (hkl)] are: 3.56 (100) (310); 3.37 (75) ($\bar{2}$31); 3.79 (60) (012); 3.03 (60) (032). In the crystal structure [R1 = 0.024 for 2655 reflections with I > 2σ(I)], thallium adopts various coordinations extending from quasi-linear to quasi-tetrahedral. Antimony forms Sb–Sb pairs, which lead to the formula [Tl+1]4[Sb2]4+[S2–]4. Biagioniite is isostructural with dervillite, Ag2AsS2. The new mineral has been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2019–120) and named for Cristian Biagioni, Associate Professor of Mineralogy at the Department of Earth Sciences of the University of Pisa, Italy.

Hingganite-(Nd), Nd2□Be2Si2O8(OH)2, a new gadolinite-supergroup mineral from Zagi Mountain, Pakistan

2020 ◽  
Vol 58 (5) ◽  
pp. 549-562
Author(s):  
Anatoly V. Kasatkin ◽  
Fabrizio Nestola ◽  
Radek Škoda ◽  
Nikita V. Chukanov ◽  
Atali A. Agakhanov ◽  
...  
Keyword(s):  
New Mineral ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Average Chemical Composition ◽  
X Ray ◽  
Conchoidal Fracture ◽  
Icp Ms ◽  
Optical Axes ◽  
Mohs Hardness ◽  
Khyber Pakhtunkhwa Province

ABSTRACT Hingganite-(Nd), ideally Nd2□Be2Si2O8(OH)2, is a new gadolinite group, gadolinite supergroup mineral discovered at Zagi Mountain, near Kafoor Dheri, about 4 km S of Warsak and 30 km NW of Peshawar, Khyber Pakhtunkhwa Province, Pakistan. The new mineral forms zones measuring up to 1 × 1 mm2 in loose prismatic crystals up to 0.7 cm long, where it is intergrown with hingganite-(Y). Other associated minerals include aegirine, microcline, fergusonite-(Y), and zircon. Hingganite-(Nd) is dark greenish-brown, transparent, has vitreous luster and a white streak. It is brittle and has a conchoidal fracture. No cleavage or parting are observed. Mohs hardness is 5½–6. Dcalc. = 4.690 g/cm3. Hingganite-(Nd) is non-pleochroic, optically biaxial (+), α = 1.746(5), β = 1.766(5), γ = 1.792(6) (589 nm). 2Vmeas. = 80(7)°; 2Vcalc. = 84°. Dispersion of optical axes was not observed. The average chemical composition of hingganite-(Nd) is as follows (wt.%; electron microprobe, BeO, B2O3, and Lu2O3 content measured by LA-ICP-MS; H2O calculated by stoichiometry): BeO 9.64, CaO 0.45, MnO 0.10, FeO 3.03, B2O3 0.42, Y2O3 8.75, La2O3 1.63, Ce2O3 12.89, Pr2O3 3.09, Nd2O3 16.90, Sm2O3 5.97, Eu2O3 1.08, Gd2O3 5.15, Tb2O3 0.50, Dy2O3 2.50, Ho2O3 0.33, Er2O3 0.84, Tm2O3 0.10, Yb2O3 0.44, Lu2O3 0.04, ThO2 0.13, SiO2 23.55, H2O 2.72, total 100.25. The empirical formula calculated on the basis of 2 Si apfu is (Nd0.513Ce0.401Y0.395Sm0.175Gd0.145Pr0.096Dy0.068La0.051Ca0.041Eu0.031Er0.022Tb0.014Yb0.011Ho0.009Tm0.003Th0.003Lu0.001)Σ1.979(□0.778Fe2+0.215Mn0.007)Σ1.000(Be1.967B0.062)Σ2.029Si2O8.46(OH)1.54. Hingganite-(Nd) is monoclinic, space group P21/c with a = 4.77193(15), b = 7.6422(2), c = 9.9299(2) Å, β = 89.851(2)°, V = 362.123(14) Å3, and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.105 (95) (011), 4.959 (56) (002), 4.773 (100) (100), 3.462 (58) (102), 3.122 , 3.028 (61) (013), 2.864 (87) (121), 2.573 (89) (113). The crystal structure of hingganite-(Nd) was refined from single-crystal X-ray diffraction data to R = 0.034 for 2007 unique reflections with I &gt; 2σ(I). The new mineral is named as an analogue of hingganite-(Y), hingganite-(Yb), and hingganite-(Ce), but with Nd dominant among the rare earth elements.

Kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], a new mineral from Ploskaya, Kola Peninsula, Russia

2018 ◽  
Vol 82 (5) ◽  
pp. 1049-1055 ◽  
Author(s):  
Daniel Atencio ◽  
Marcelo B. Andrade ◽  
Luca Bindi ◽  
Paola Bonazzi ◽  
Matteo Zoppi ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Northern Region ◽  
Complete Characterization ◽  
New Mineral ◽  
X Ray Diffraction ◽  
International Mineralogical Association ◽  
Cell Parameters ◽  
Mohs Hardness

ABSTRACTThis study presents a complete characterization of kenoplumbomicrolite, (Pb,□)2Ta2O6[□,(OH),O], occurring in an amazonite pegmatite from Ploskaya Mountain, Western Keivy Massif, Kola Peninsula, Murmanskaja Oblast, Northern Region, Russia.Kenoplumbomicrolite occurs in yellowish brown octahedral, cuboctahedral and massive crystals, up to 20 cm, has a white streak, a greasy lustre and is translucent. The Mohs hardness is ~6. Attempts to measure density (7.310–7.832 g/cm3) were affected by the ubiquitous presence of uraninite inclusions. Reflectance values were measured in air and immersed in oil. Kenoplumbocrolite is optically isotropic. The empirical formula is (Pb1.30□0.30Ca0.29Na0.08U0.03)Σ2.00(Ta0.82Nb0.62Si0.23Sn4+0.15Ti0.07Fe3+0.10Al0.01)Σ2.00O6[□0.52(OH)0.25O0.23]Σ1.00 (from the crystal used for the structural study) and (Pb1.33□0.66Mn0.01)Σ2.00(Ta0.87Nb0.72Sn4+0.18Fe3+0.11W0.08Ti0.04)Σ2.00O6[□0.80(OH)0.10O0.10]Σ1.00 (average including additional fragments). The mineral is cubic, space group Fd$\overline 3 $m. The unit-cell parameters refined from powder X-ray diffraction data are a = 10.575(2) Å and V = 1182.6(8) Å3, which are in accord with those obtained previously from a single crystal of a = 10.571(1) Å, V = 1181.3(2) Å3 and Z = 8. The mineral description and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA2015-007a).

scholarly journals Nixonite, Na2Ti6O13, a new mineral from a metasomatized mantle garnet pyroxenite from the western Rae Craton, Darby kimberlite field, Canada

2019 ◽  
Vol 104 (9) ◽  
pp. 1336-1344
Author(s):  
Chiara Anzolini ◽  
Fei Wang ◽  
Garrett A. Harris ◽  
Andrew J. Locock ◽  
Dongzhou Zhang ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Mantle Xenoliths ◽  
New Mineral ◽  
Monoclinic Space Group ◽  
Calculated Density ◽  
Cell Parameters ◽  
Garnet Pyroxenite ◽  
Mohs Hardness ◽  
Kimberlite Field ◽  
Metasomatized Mantle

Abstract Nixonite (IMA 2018-133), ideally Na2Ti6O13, is a new mineral found within a heavily metasomatized pyroxenite xenolith from the Darby kimberlite field, beneath the west-central Rae Craton, Canada. It occurs as microcrystalline aggregates, 15 to 40 μm in length. Nixonite is isostructural with jeppeite, K2Ti6O13, with a structure consisting of edge- and corner-shared titanium-centered octahedra that enclose alkali-metal ions. The Mohs hardness is estimated to be between 5 and 6 by comparison to jeppeite, and the calculated density is 3.51(1) g/cm3. Electron microprobe wavelength-dispersive spectroscopic analysis (average of 6 points) yielded: Na2O 6.87, K2O 5.67, CaO 0.57, TiO2 84.99, V2O3 0.31, Cr2O3 0.04, MnO 0.01, Fe2O3 0.26, SrO 0.07, total 98.79 wt%. The empirical formula, based on 13 O atoms, is: (Na1.24K0.67Ca0.06)Σ1.97(Ti5.96V0.023Fe0.018)Σ6.00O13 with minor amounts of Cr and Mn. Nixonite is monoclinic, space group C2/m, with unit-cell parameters a = 15.3632(26) Å, b = 3.7782(7) Å, c = 9.1266(15) Å, β = 99.35(15)°, and V = 522.72(1) Å3, Z = 2. Based on the average of seven integrated multi-grain diffraction images, the strongest diffraction lines are [dobs in Å (I in %) (hkl)]: 3.02 (100) (310), 3.66 (75) (110), 7.57 (73) (200), 6.31 (68) (201), 2.96 (63) (311), 2.96 (63) (203), and 2.71 (62) (402). The five main Raman peaks of nixonite, in order of decreasing intensity, are at 863, 280, 664, 135, and 113 cm–1. Nixonite is named after Peter H. Nixon, a renowned scientist in the field of kimberlites and mantle xenoliths. Nixonite occurs within a pyroxenite xenolith in a kimberlite, in association with rutile, priderite, perovskite, freudenbergite, and ilmenite. This complex Na-K-Ti-rich metasomatic mineral assemblage may have been produced by a fractionated Na-rich kimberlitic melt that infiltrated a mantle-derived garnet pyroxenite and reacted with rutile during kimberlite crystallization.

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