Imayoshiite, Ca3Al(CO3)[B(OH)4](OH)6·12H2O, a new mineral of the ettringite group from Ise City, Mie Prefecture, Japan

2015 ◽  
Vol 79 (2) ◽  
pp. 413-423 ◽  
Author(s):  
D. Nishio-Hamane ◽  
M. Ohnishi ◽  
K. Momma ◽  
N. Shimobayashi ◽  
R. Miyawaki ◽  
...  
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
White Light ◽  
New Mineral ◽  
Structural Refinement ◽  
Single Crystal Diffraction ◽  
Ettringite Group ◽  
Mohs Hardness ◽  
White Streak

AbstractImayoshiite, Ca3Al(CO3)[B(OH)4](OH)6·12H2O, occurs in cavities in the altered gabbro xenolith in the sepentinized dunite exposed at Suisho-dani, Ise City, Mie Prefecture, Japan. Imayoshiite is colourless and transparent with a vitreous lustre and its aggregates are white with a silky lustre. Imayoshiite has a white streak. Its Mohs hardness is 2–3. It is brittle, the cleavage is distinct on {100} and the fracture is uneven. The mineral is uniaxial (–) with the indices of refraction ω = 1.497(2) and ε = 1.470(2) in white light. Imayoshiite is hexagonal, P63, a = 11.0264(11), c = 10.6052(16) Å by powder diffraction and a = 11.04592(2), c = 10.61502(19) Å by single-crystal diffraction. The structural refinement converged to R1 = 2.35%. Imayoshiite is the first member of the ettringite group with both CO3 and B(OH)4 anions.

Whiteite-(CaMnMn), CaMnMn2Al2[PO4]4(OH)2·8H2O, a new mineral from the Hagendorf-Süd granitic pegmatite, Germany

2012 ◽  
Vol 76 (7) ◽  
pp. 2761-2771 ◽  
Author(s):  
V. N. Yakovenchuk ◽  
E. Keck ◽  
S. V. Krivovichev ◽  
Y. A. Pakhomovsky ◽  
E. A. Selivanova ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Granitic Pegmatite ◽  
New Mineral ◽  
Charge Balance ◽  
Single Crystal Diffraction ◽  
Mohs Hardness ◽  
The Mean

AbstractWhiteite-(CaMnMn), CaMnMn2Al2[PO4]4(OH)2·8H2O, is a new hydrous phosphate of Ca, Mn and Al, which is closely related to both jahnsite-(CaMnMn) and the minerals of the whiteite group. It is monoclinic, P2/a, with a = 15.02(2), b = 6.95(1), c =10.13(3) Å, β = 111.6(1)°, V = 983.3(6) Å3, Z = 2 (from powder diffraction data) or a = 15.020(5), b = 6.959(2), c = 10.237(3) Å, β = 111.740(4)°, V = 984.3(5) Å3, Z = 2 (from single-crystal diffraction data). The mineral was found in the Hagendorf Süd granitic pegmatite (Germany) as small (up to 0.5 mm in size) crystals elongated on a and tabular on {010}. The crystals are either simply or polysynthetically twinned on {001}. They crystallize on the walls of voids within altered zwieselite crystals or form coronas (up to 1 mm in diameter) around cubic crystals of uraninite. The mineral is transparent, colourless to pale yellow (depending on Al–Fe3+ substitution), with a vitreous lustre and a white streak. The cleavage is perfect on {001}, the fracture is stepped and the Mohs hardness is 3½. In transmitted light, the mineral is colourless; dispersion was not observed. Whiteite-(CaMnMn) is biaxial (+), α = 1.589(2), β = 1.592(2), γ = 1.601(2) (589 nm), 2Vmeas = 60(10)°, 2Vcalc = 60.3°. The optical orientation is X = b, Z^a = 5°. The calculated and measured densities are Dcalc = 2.768 and Dmeas = 2.70(3) g cm–3, respectively. The mean chemical composition determined by electron microprobe is Na2O 0.53, MgO 0.88, Al2O3 11.66, P2O5 34.58, CaO 4.29, MnO 17.32, FeO 8.32, ZnO 2.60 wt.%, with H2O 19.50 wt.% (determined by the Penfield method), giving a total of 99.68 wt.%. The empirical formula calculated on the basis of four phosphorus atoms per formula unit, with ferric iron calculated to maintain charge balance, is (Ca0.63Zn0.26Na0.14)Σ1.03(Mn0.60Fe0.402+)Σ1.00(Mn1.40Fe0.372+Mg0.18Fe0.063+)Σ2.01(Al1.88Fe0.123+)Σ2.00[PO4]4(OH)2·7.89H2O. The simplified formula is CaMnMn2Al2[PO4]4(OH)2·8H2O. The mineral is easily soluble in 10% HCl at room temperature. The strongest X-ray powder-diffraction lines [listed as d in Å (I) (hkl)] are as follows: 9.443(65)(001), 5.596(25)(011), 4.929(80)(210), 4.719(47)(002), 3.494(46)(400), 2.7958(100)(022). The crystal structure of whiteite-(CaMnMn) was refined for a single crystal twinned on (001) to R1 = 0.068 on the basis of 5702 unique observed reflections. It is similar to the structures of other members of the whiteite group. The mineral is named for the chemical composition, in accordance with whiteite-group nomenclature.

Mauriziodiniite, NH4(As2O3)2I, the ammonium and iodine analogue of lucabindiite from the Torrecillas mine, Iquique Province, Chile

2019 ◽  
Vol 84 (2) ◽  
pp. 267-273
Author(s):  
Anthony R. Kampf ◽  
Barbara P. Nash ◽  
Arturo A. Molina Donoso
Keyword(s):  
White Light ◽  
Electron Microprobe ◽  
Empirical Formula ◽  
New Mineral ◽  
Calculated Density ◽  
Secondary Alteration ◽  
Layer Sequence ◽  
Mohs Hardness ◽  
Elastic Fracture ◽  
White Streak

AbstractThe new mineral mauriziodiniite (IMA2019-036), NH4(As2O3)2I, was found at the Torrecillas mine, Iquique Province, Chile, where it is a secondary alteration phase associated with calcite, cuatrocapaite-(NH4), lavendulan, magnesiokoritnigite and torrecillasite on matrix consisting of native arsenic, arsenolite and pyrite. Mauriziodiniite occurs as hexagonal tablets up to ~300 μm in diameter. Crystals are colourless and transparent, with pearly to adamantine lustre and white streak. The Mohs hardness is ~1. Tablets are sectile and easily flexible, but not elastic. Fracture is curved, irregular and stepped. Cleavage is perfect on {001}. The calculated density is 3.916 g/cm3. Optically, mauriziodiniite is uniaxial (–) with ω = 2.07(calc) and ɛ = 1.770(5) (white light). The empirical formula, determined from electron microprobe analyses, is (NH4)0.94K0.03(As2O3)2I0.92Cl0.03. Mauriziodiniite is hexagonal, P6/mmm, a = 5.289(2), c = 9.317(2) Å, V = 225.68(18) Å3 and Z = 1. The structure, refined to R1 = 4.16% for 135 Io > 2σI reflections, contains three types of layers: (1) a planar neutral As2O3 (arsenite) sheet; (2) an NH4+ layer that links adjacent arsenite sheets via bonds to their O atoms; and (3) an I– layer that links adjacent arsenite sheets via bonds to their As atoms. The layer sequence is I–As2O3–NH4–As2O3–I. Mauriziodiniite is isostructural with lucabindiite and is structurally related to gajardoite, cuatrocapaite-(NH4), cuatrocapaite-(K) and torrecillasite.

Canutite, NaMn3[AsO4][AsO3(OH)]2, a new protonated alluaudite-group mineral from the Torrecillas mine, Iquique Province, Chile

2014 ◽  
Vol 78 (4) ◽  
pp. 787-795 ◽  
Author(s):  
A. R. Kampf ◽  
S. J. Mills ◽  
F. Hatert ◽  
B. P. Nash ◽  
M. Dini ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
White Light ◽  
Electron Microprobe ◽  
New Mineral ◽  
Optical Orientation ◽  
Calculated Density ◽  
Secondary Alteration ◽  
Group Mineral ◽  
X Ray ◽  
Mohs Hardness

AbstractThe new mineral canutite (IMA2013-070), NaMn3[AsO4][AsO3(OH)]2, was found at two different locations at the Torrecillas mine, Salar Grande, Iquique Province, Chile, where it occurs as a secondary alteration phase in association with anhydrite, halite, lavendulan, magnesiokoritnigite, pyrite, quartz and scorodite. Canutite is reddish brown in colour. It forms as prisms elongated on [20] and exhibiting the forms {010}, {100}, {10}, {201} and {102}, or as tablets flattened on {102} and exhibiting the forms {102} and {110}. Crystals are transparent with a vitreous lustre. The mineral has a pale tan streak, Mohs hardness of 2½, brittle tenacity, splintery fracture and two perfect cleavages, on {010} and {101}. The calculated density is 4.112 g cm−3. Optically, canutite is biaxial (+) with α = 1.712(3), β = 1.725(3) and γ = 1.756(3) (measured in white light). The measured 2V is 65.6(4)°, the dispersion is r < v (slight), the optical orientation is Z = b; X ^ a = 18° in obtuse β and pleochroism is imperceptible. The mineral is slowly soluble in cold, dilute HCl. The empirical formula (for tabular crystals from near the mineshaft), determined from electron - microprobe analyses, is (Na1.05Mn2.64Mg0.34Cu0.14Co0.03)∑4.20As3O12H1.62. Canutite is monoclinic, C2/c, a = 12.3282(4), b = 12.6039(5), c = 6.8814(5) Å, β = 113.480(8)°, V = 980.72(10) Å3 and Z = 4. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 6.33(34)(020), 4.12(26)(21), 3.608(29)(310,31), 3.296(57)(12), 3.150(28)(002,131), 2.819(42)(400,041,330), 2.740(100)(240,02,112) and 1.5364(31)(multiple). The structure, refined to R1 = 2.33% for 1089 Fo > 4σF reflections, shows canutite to be isostructural with protonated members of the alluaudite group.

scholarly journals Chirvinskyite, (Na,Ca)13(Fe,Mn,□)2(Ti,Nb)2(Zr,Ti)3-(Si2O7)4(OH,O,F)12, a New Mineral with a Modular Wallpaper Structure, from the Khibiny Alkaline Massif (Kola Peninsula, Russia)

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 219
Author(s):  
Victor Yakovenchuk ◽  
Yakov Pakhomovsky ◽  
Taras Panikorovskii ◽  
Andrey Zolotarev ◽  
Julia Mikhailova ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Empirical Formula ◽  
Inorganic Compounds ◽  
Structure Type ◽  
New Mineral ◽  
State University ◽  
Mohs Hardness ◽  
Alkaline Massif ◽  
Khibiny Alkaline Massif ◽  
White Streak

Chirvinskyite, (Na,Ca)13(Fe,Mn,□)2(Ti,Nb)2(Zr,Ti)3(Si2O7)4(OH,O,F)12, is a new wöhlerite–related zirconotitano–sorosilicate. It is triclinic, P1, a = 7.0477(5), b = 9.8725(5), c = 12.2204(9) Å, α = 77.995(5), β = 82.057(6), γ = 89.988(5)°, V = 823.35(9) Å3, Z = 1. The mineral was found in albitized alkaline pegmatites in a foyaite of the Mt. Takhtarvumchorr (Khibiny alkaline massif, Kola Peninsula, Russia, N 67°40’, E 33°33’). Chirvinskyite forms sheaf–like and radiated aggregates (up to 6 mm in diameter) of split fibrous crystals hosted by saccharoidal fluorapatite and albite. The mineral is pale cream in color, with a silky luster and a white streak. The cleavage is not recognized. Mohs hardness is 5. Chirvinskyite is biaxial (–), α 1.670(2), β 1.690(2), γ 1.705(2) (589 nm), 2Vcalc = 80.9°. The calculated and measured densities are 3.41 and 3.07(2) g·cm−3, respectively. The empirical formula based on Si = 8 apfu is (Na9.81Ca3.28K0.01)∑13.10(Fe0.72Mn0.69□0.54Mg0.05)∑2.00 (Ti1.81Nb0.19)∑2.00(Zr2.27Ti0.63)∑2.90(Si2O7)4{(OH)5.94O3.09F2.97}∑12.00. Chirvinskyite belongs to a new structure type of minerals and inorganic compounds and is related to the wöhlerite-group minerals. Its modular “wallpaper” structure consists of disilicate groups Si2O7 and three types of “octahedral walls”. The mineral is named in honor of Petr Nikolaevich Chirvinsky (1880–1955), Russian geologist and petrographer, head of the Petrography Department of the Perm’ State University (1943–1953), for his contributions to mineralogy and petrology, including studies of the Khibiny alkaline massif.

scholarly journals Parisite-(La), ideally CaLa2(CO3)3F2, a new mineral from Novo Horizonte, Bahia, Brazil

2018 ◽  
Vol 82 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Luiz A. D. Menezes Filho ◽  
Mario L. S. C. Chaves ◽  
Nikita V. Chukanov ◽  
Daniel Atencio ◽  
Ricardo Scholz ◽  
...  
Keyword(s):  
Single Crystal ◽  
Ir Spectrum ◽  
Empirical Formula ◽  
New Mineral ◽  
Formula Unit ◽  
Calculated Density ◽  
Oh Groups ◽  
Space Group ◽  
X Ray ◽  
Mohs Hardness

ABSTRACTParisite-(La) (IMA2016-031), ideally CaLa2(CO3)3F2, occurs in a hydrothermal vein crosscutting a metarhyolite of the Rio dos Remédios Group, at the Mula mine, Tapera village, Novo Horizonte county, Bahia, Brazil, associated with hematite, rutile, almeidaite, fluocerite-(Ce), brockite, monazite-(La), rhabdophane-(La) and bastnäsite-(La). Parisite-(La) occurs as residual nuclei (up to 5 mm) in steep doubly-terminated pseudo-hexagonal pyramidal crystals (up to 8.2 cm). Parisite-(La) is transparent, yellow-green to white, with a white streak and displays a vitreous (when yellow-green) to dull (when white) lustre. Cleavage is distinct on pseudo-{001}; fracture is laminated, conchoidal, or uneven. The Mohs hardness is 4 to 5, and it is brittle. Calculated density is 4.273 g cm−3. Parisite-(La) is pseudo-uniaxial (+), ω = 1.670(2) and ε = 1.782(5) (589 nm). The empirical formula normalized on the basis of 11 (O + F) atoms per formula unit (apfu) is Ca0.98(La0.83Nd0.51Ce0.37Pr0.16Sm0.04Y0.03)Σ1.94C3.03O8.91F2.09. The IR spectrum confirms the absence of OH groups. Single-crystal X-ray studies gave the following results: monoclinic (pseudo-trigonal), space group: C2, Cm, or C2/m, a = 12.356(1) Å, b = 7.1368(7) Å, c = 28.299(3) Å, β = 98.342(4)°, V = 2469.1(4) Å3 and Z = 12. Parisite-(La) is the La-dominant analogue of parisite-(Ce).

Raberite, Tl5Ag4As6SbS15, a new Tl-bearing sulfosalt from Lengenbach quarry, Binn valley, Switzerland: description and crystal structure

2012 ◽  
Vol 76 (5) ◽  
pp. 1153-1163 ◽  
Author(s):  
L. Bindi ◽  
F. Nestola ◽  
A. Guastoni ◽  
L. Peruzzo ◽  
M. Ecker ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Vickers Hardness ◽  
New Mineral ◽  
Formula Unit ◽  
Triclinic Space Group ◽  
Light Blue ◽  
Reflected Light ◽  
Mohs Hardness ◽  
The Mean

AbstractRaberite, ideally Tl5Ag4As6SbS15, is a new mineral from Lengenbach quarry in the Binn Valley, Valais, Switzerland. It occurs very rarely as euhedral crystals up to 150 m m across associated with yellow needle-like smithite, realgar, hatchite and probable trechmannite, edenharterite, jentschite and two unidentified sulfosalts. Raberite is opaque with a metallic lustre and has a dark brown–red streak. It is brittle with a Vickers hardness (VHN10) of 52 kg mm–2 (range 50–55) corresponding to a Mohs hardness of 2½–3. In reflected light raberite is moderately bireflectant and very weakly pleochroic from light grey to a slightly greenish grey. It is very weakly anisotropic with greyish to light blue rotation tints between crossed polars. Internal reflections are absent. Reflectance percentages for the four COM wavelengths [listed as Rmin, Rmax, (λ)] are 30.6, 31.8 (471.1 nm), 28.1, 29.3 (548.3 nm), 27.1, 28.0 (586.6 nm), and 25.8, 26.9 (652.3 nm).Raberite is triclinic, space group P1, with a = 8.920(1), b = 9.429(1), c = 20.062(3) Å, α = 79.66(1), β = 88.84(1), γ = 62.72(1)º, V = 1471.6(4) Å3 and Z = 2. The crystal structure [R1 = 0.0827 for 2110 reflections with I > 2σ(I)] consists of columns of nine-coordinate Tl atoms forming irregular polyhedra extending along [001] and forming sheets parallel to (010). The columns are decorated by cornersharing MS3 pyramids (M = As, Sb) and linked by AgS3 triangles. Of the seven M positions, one is dominated by Sb and the others by As; the mean M-S bond distances reflect As ↔ Sb substitution at these sites.The eight strongest lines in the powder diffraction pattern [dcalc in Å (I) (hkl)] are: 3.580 (100) (11̄3); 3.506 (58) (1̄23); 3.281 (73) (006); 3.017 (54) (1̄2̄3); 3.001 (98) (133); 2.657 (51) (226); 2.636 (46) (300); 2.591 (57) (330). A mean of 9 electron microprobe analyses gave Tl 39.55(13), Ag 18.42(8), Cu 0.06(2), As 17.08(7), Sb 5.61(6), S 19.15(11); total 99.87 wt.%, which corresponds to Tl4.85Ag4.28Cu0.02As5.72Sb1.16S14.97 with 31 atoms per formula unit. The new mineral has been approved by the IMA-CNMNC Commission (IMA 2012-017) and is named for Thomas Raber, an expert on Lengenbach minerals.

Eldfellite, NaFe(SO4)2, a new fumarolic mineral from Eldfell volcano, Iceland

2009 ◽  
Vol 73 (1) ◽  
pp. 51-57 ◽  
Author(s):  
T. Balić-Žunic ◽  
A. Garavelli ◽  
P. Acquafredda ◽  
E. Leonardsen ◽  
S. P. Jakobsson
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
New Mineral ◽  
Synthetic Compound ◽  
Calculated Density ◽  
Yellowish Green ◽  
Diffraction Diagram ◽  
White Streak

A new mineral, eldfellite, was found among fumarolic encrustations collected in 1990 on the Eldfell volcano, Heimaey Island, Iceland. Associated minerals are ralstonite, anhydrite, gypsum, bassanite, hematite, opal and tamarugite, as well as a presumably new mineral with the composition Na3Fe(SO4)3. Along with opal and tamarugite, eldfellite forms soft and fragile aggregates built of thin, platy crystals of micrometre size. The mineral is yellowish-green to greenish-white, with a white streak. The calculated density is 3.062 g/cm3. Eldfellite is monoclinic, C2/m, a 8.043(4) Å, b 5.139(2) Å, c 7.115(4) Å, β 92.13(2)º, Vuc 293.9(2) Å3, Z = 2 and is isostructural with yavapaiite[KFe (SO4)2]. The strongest lines in the powder diffraction diagram are [d (Å), I (relative to 10)]: 3.72, 8; 3.64, 5; 3.43, 5; 2.77, 10; 2.72, 6; 2.57, 3; 2.370, 6; 1.650, 3. Theche mical analysis and theX-ray diffraction data of eldfellite correspond to those of the synthetic compound NaFe(SO4)2.

scholarly journals Decrespignyite-(Y), a new copper yttrium rare earth carbonate chloride hydrate from Paratoo, South Australia

2002 ◽  
Vol 66 (1) ◽  
pp. 181-188 ◽  
Author(s):  
K. Wallwork ◽  
U. Kolitsch ◽  
A. Pring ◽  
L. Nasdala
Keyword(s):  
Rare Earth ◽  
Powder Diffraction ◽  
Country Rock ◽  
Mining Industry ◽  
South Australia ◽  
New Mineral ◽  
Calculated Density ◽  
Mohs Hardness ◽  
The University ◽  
Chloride Hydrate

AbstractDecrespignyite-(Y) is a new copper yttrium rare earth carbonate chloride hydrate from the Paratoo copper mine, near Yunta, Olary district, South Australia. Decrespignyite-(Y) occurs as blue crusts, coatings and fillings in thin fissures on the slatey country rock. Individual pseudohexagonal platelets are typically 10–50 µm in maximum dimension and are often curved. Associated minerals include caysichite-(Y), donnayite-(Y), malachite and kamphaugite-(Y). Electron microprobe and CHN analyses gave: Y2O3 42.2; La2O3 0.1; Pr2O3 0.1; Nd2O3 1.3; Sm2O3 1.0; Gd2O3 4; Tb2O3 0.4; Dy2O3 3.7; Ho2O3 2.6; Er2O3 2.5; CaO 0.5; CuO 10.9; Cl 3.0; CO2 19.8; H2O 10.8, yielding an empirical formula of (Y3.08Gd0.22Dy0.16Ho0.11Er0.10Nd0.06Sm0.05Tb0.02La0.02Pr0.01Ca0.08)∑3.91Cu1.12(CO3)3.70-Cl0.7(OH)5.79·2.4H2O. The simplified formula is (Y,REE)4Cu(CO3)4Cl(OH)5·2H2O. The mineral is royal blue to turquoise-blue in colour, transparent, with a pearly to vitreous lustre and a pale blue streak. No cleavage was observed but the morphology suggests that cleavage would be on [010]. The Mohs' hardness is estimated to be 4. The strongest lines in the X-ray powder pattern are {dobs (Iobs) (hkl)} 22.79 (30) (010); 7.463 (30) (001); 7.086 (50) (011); 6.241 (100) (021); 4.216 (30) (l̄12); 3.530 (40) (022); 3.336 (30) (032); 2.143 (30) (222, 4̄01). The powder diffraction pattern was indexed on a monoclinic cell with a = 8.899(6), b = 22.77(2), c = 8.589(6)Å, β = 120.06(5)°, V = 1506.3(7) Å3 and Z = 4. The structure of the new mineral could not be determined but powder diffraction data indicate the space group is P2, Pm or P2/m. The measured density is 3.64(2) g/cm3 and the calculated density is 3.645 g/cm3. Decrespignyite-(Y) is biaxial negative with α = 1.604(4) and γ = 1.638(3) with β very close to γ pleochroism is medium strong; X very pale bluish, Y and Z bluish (with greenish tint). Decrespignyite-(Y) is a supergene mineral which precipitated from mildly basic carbonated ground waters. The mineral is named after Robert Champion de Crespigny, a prominent figure in the Australian mining industry and chancellor of the University of Adelaide.

Kudryavtsevaite, Na3MgFe3+Ti4O12, a new kimberlitic mineral

2013 ◽  
Vol 77 (3) ◽  
pp. 327-334 ◽  
Author(s):  
S. Anashkin ◽  
A. Bovkun ◽  
L. Bindi ◽  
V. Garanin ◽  
Y. Litvin
Keyword(s):  
Crystal Structure ◽  
Powder Diffraction ◽  
Vickers Hardness ◽  
New Mineral ◽  
Scientific School ◽  
State University ◽  
Orthorhombic Space Group ◽  
Reflected Light ◽  
Black Streak ◽  
Mohs Hardness

AbstractKudryavtsevaite, ideally Na3MgFe3+Ti4O12, is a new mineral from kimberlitic rocks of the Orapa area, Botswana. It occurs as rare prismatic crystals, up to 100 μm m across, associated with Mg-rich ilmenite, freudenbergite and ulvöspinel. Kudryavtsevaite is opaque with a vitreous lustre and shows a black streak. It is brittle; the Vickers hardness (VHN100) is 901 kg mm−2 (range: 876–925) (Mohs hardness ∼6). In reflected light, kudryavtsevaite is moderately bireflectant and very weakly pleochroic from dark grey to a slightly bluish grey. Under crossed polars, it is very weakly anisotropic with greyish-bluish rotation tints. Internal reflections are absent. Reflectance values (%), Rmin and Rmax, are: 21.3, 25.4 (471.1 nm), 20.6, 24.1 (548.3 nm), 20.0, 23.5 (586.6 nm) and 19.1, 22.4 (652.3 nm).Kudryavtsevaite is orthorhombic, space group Pnma, with a = 27.714(1), b = 2.9881(3), c = 11.3564(6) Å, V = 940.5(1) Å3, and Z = 4. The crystal structure [R1 = 0.0168 for 819 reflections with I > 2σ(I)] consists of edge-sharing and corner-sharing chains composed of Mg, Fe3+ and Ti atoms coordinated by six atoms of oxygen and running along the b axis, with Na filling the tunnels formed by the chains. The eight strongest powder-diffraction lines [d in Å (I/I0) (hkl)] are: 7.17 (100) (301), 4.84 (70) (302), 2.973 (35) (901), 2.841 (50) (004), 2.706 (50) (902), 2.541 (50) (312), 2.450 (70) (611), and 2.296 (45) (612). The average results of 12 electron microprobe analyses gave (wt.%): Na2O 16.46(15), CaO 1.01(3), MgO 5.31(5), Fe2O3 22.24(32), Cr2O3 1.05(6), Al2O3 0.03(2), TiO2 53.81(50), total 99.91, corresponding to the empirical formula (Na2.89Ca0.10)Σ2.99(Ti3.67Fe1.523+Mg0.72Cr0.08)Σ5.99O12, or ideally Na3MgFe3+Ti4O12.The new mineral has been approved by the IMA-CNMNC and named for Galina Kudryavtseva (1947–2006), a well known Russian mineralogist and founder of the Diamond Mineralogy Laboratory and scientific school for investigation of diamond mineralogy and geochemistry at the Lomonosov State University in Moscow, Russia.

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