Leisingite, Cu(Mg,Cu,Fe,Zn)2Te6+O6·6H2O, a new mineral species from the Centennial Eureka mine, Juab County, Utah

1996 ◽  
Vol 60 (401) ◽  
pp. 653-657 ◽  
Author(s):  
Andrew C. Roberts ◽  
Lee A. Groat ◽  
Joel D. Grice ◽  
Robert A. Gault ◽  
Martin C. Jensen ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Infrared Absorption Spectrum ◽  
Thin Plates ◽  
New Mineral ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Pale Yellow ◽  
Orange Yellow ◽  
New Mineral Species

AbstractLeisingite, ideally Cu(Mg,Cu,Fe,Zn)2Te6+O6·6H2O, is hexagonal, P3 (143), with unit-cell parameters refined from powder data: a = 5.305(1), c = 9.693(6) Å, V = 236.2(2) Å3, c/a = 1.8271, Z = 1. The strongest six reflections of the X-ray powder-diffraction pattern [d in Å (I) (hkl)] are: 9.70 (100) (001), 4.834 (80) (002), 4.604 (60) (100), 2.655 (60) (110), 2.556 (70) (111) and 2.326 (70) (112). The mineral is found on the dumps of the Centennial Eureka mine, Juab County, Utah U.S.A. where it occurs as isolated, or rarely as clusters of, hexagonal-shaped very thin plates or foliated masses in small vugs of crumbly to drusy white to colourless quartz. Associated minerals are jensenite, cesbronite and hematite. Individual crystals are subhedral to euhedral and average less than 0.1 mm in size. Cleavage {001} perfect. Forms are: {001} major; {100}, {110} minute. The mineral is transparent to somewhat translucent, pale yellow to pale orange-yellow, with a pale yellow streak and an uneven fracture. Leisingite is vitreous with a somewhat satiny to frosted appearance, brittle to somewhat flexible and nonfluorescent; H(Mohs) 3–4; D(calc.) 3.41 for the idealized formula; uniaxial negative, ω = 1.803(3), ɛ = 1.581 (calc.). Averaged electron-microprobe analyses yielded CuO 24.71, FeO 6.86, MgO 6.19, ZnO 0.45, TeO3 36.94, H2O (calc.) [21.55], total [96.70] wt.%, leading to the empirical formula based on O = 12. The infrared absorption spectrum shows definite bands for structural H2O with an O-H stretching frequency centered at 3253 cm−1 and a H-O-H flexing frequency centered at 1670 cm−l. The mineral name honours Joseph F. Leising, Reno, Nevada, who helped collect the discovery specimens.

scholarly journals Crystallochemical aspects of two microlite-group new mineral species

2014 ◽  
Vol 70 (a1) ◽  
pp. C1095-C1095
Author(s):  
Marcelo Andrade ◽  
Javier Ellena ◽  
Daniel Atencio
Keyword(s):  
Microprobe Analysis ◽  
Electron Microprobe Analysis ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Group 1

Fluorcalciomicrolite, Ca1.5Ta2O6F, and hydroxycalciomicrolite, Ca1.5Ta2O6(OH), are new microlite-group [1] minerals found in the Volta Grande pegmatite, Nazareno, Minas Gerais, Brazil. Both occur as octahedral and rhombododecahedral crystals. The crystals are colourless, yellow and translucent, with vitreous to resinous luster. The densities calculated for fluorcalciomicrolite [2] and hydroxycalciomicrolite are 6.160 and 6.176 g/cm3, respectively. The empirical formulae obtained from electron microprobe analysis are (Ca1.07Na0.81□0.12)Σ2(Ta1.84Nb0.14Sn0.02)Σ2[O5.93(OH)0.07]Σ6.00[F0.79(OH)0.21] for fluorcalciomicrolite and (Ca1.48Na0.06Mn0.01)Σ1.55(Ta1.88Nb0.11Sn0.01)Σ2O6[(OH)0.76F0.20O0.04] for hydroxycalmicrolite. Fluorcalciomicrolite is cubic, space group Fd-3m, a = 10.4191(6) Å, V = 1131.07(11) Å3, and Z = 8. Hydroxycalciomicrolite is also cubic; however, the presence of P-lattice is confirmed by the large number of weak reflections observed by X-ray diffraction. As a result, the space group is P4332 and unit-cell parameters are a = 10.4211(8) Å, and V = 1131.72(15) Å3.

Juabite, Cu5(Te6+O4)2(As5+O4)2.3H2O. a new mineral species from the Centennial Eureka mine, Juab County, Utah

1997 ◽  
Vol 61 (404) ◽  
pp. 139-144 ◽  
Author(s):  
Andrew C. Roberts ◽  
Robert A. Gault ◽  
Martin C. Jensen ◽  
Alan J. Criddle ◽  
Elizabeth A. Moffatx
Keyword(s):  
Infrared Absorption Spectrum ◽  
New Mineral ◽  
Polished Section ◽  
Triclinic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Reflected Light ◽  
O 19 ◽  
Pale Green

AbstractJuabite, ideally Cu5(Te6+O4)2(As5+O4)2·3H2O, is triclinic, space-group choices P1(1) or P(2), with unit-cell parameters refined from powder data: a = 8.984(5), b = 10.079(7), c = 8.975(5) Å, α = 102.68(7)°, β = 92.45(6)°, γ = 70.45(5)° V = 746.8(8) Å3, a:b:c = 0.8914:1:0.8905, Z = 2. The strongest seven reflections of the X-ray powder-diffraction pattern [d in Å (I)(hkl)] are: 9.28 (70)(010), 4.65 (70)(020), 3.097 (100)(030,11), 3.018 (60)(212), 2.658 (50)(01), 2.468 (50)(2) and 1.740 (50)(1, 521, 5). The mineral is an extremely rare constituent on the dumps of the Centennial Eureka mine, Juab County, Utah, U.S.A., where it occurs as crystalline platy masses that average 0.2–0.3 mm in longest dimension within small interconnected vugs of drusy quartz. Associated minerals are enargite, beudantite, and an undefined, possible Pb-analogue of arsenobismite. Individual crystals are subhedral to euhedral and average 125 × 100 × 1–2 µm in size. Cleavage {010} perfect. Forms are: {010} major; {100}, {01}, and {101} minor. The mineral is translucent (masses) to transparent (crystals), emerald-green, with a pale green streak, and an uneven to subconchoidal fracture. Juabite is vitreous to adamantine (almost gemmy) on cleavage faces, brittle, and nonfluorescent; H (Mohs) 3–4; D (calc.) 4.59 g/cm3 for the idealised formula. In polished section, juabite is white in plane-polarised reflected light in air with ubiquitous turquoise-blue internal reflections; bireflectance and anisotropy are unknown (due to interference from internal reflections). Averaged electronmicroprobe analyses yielded CuO 38.25, PbO 0.57, TeO3 32.58, As2O5 22.81, H2O (calc. assuming 3H2O) [5.19], total [99.40] wt.%, leading to the empirical formula (Cu5.01Pb0.03)Σ5.04(TeO4)l.93(AsO4)2.07·3.00H2O based on O = 19. The infrared absorption spectrum shows definite bands for structural H2O with an O-H stretching frequency centred at 3283 cm−1 and a H-O-H flexing frequency centred at 1642 cm−1. The mineral name is for the county within the state of Utah in which the Centennial Eureka mine is located.

Demagistrisite, the Missing Link in a Polysomatic Series from Lawsonite to Orientite

2021 ◽  
Author(s):  
Fernando Cámara ◽  
Anthony R. Kampf ◽  
Fabrizio Nestola ◽  
Marco E. Ciriotti ◽  
Deborah Spartà ◽  
...  
Keyword(s):  
Room Temperature ◽  
New Mineral ◽  
Optical Orientation ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Orange Yellow ◽  
Cation Sites ◽  
Large Cation

Abstract Demagistrisite, ideally BaCa2Mn3+4(Si3O10)(Si2O7)(OH)4·3H2O, is a new mineral found at the Cerchiara mine (eastern Liguria, La Spezia province, Italy). The ore consists of rhythmic interlaying of braunite-bearing metasediments (5–15 cm thick) and hematite-rich cherts. Demagistrisite occurs in association with cerchiaraite-(Mn), namansilite, noelbensonite, orientite, richterite, ruizite, and saponite in matrix consisting of braunite, calcite, cryptomelane, orthoclase, and quartz. Demagistrisite crystals occur as tightly intergrown blades or as millimeter-sized prisms and needles with square cross-section, typically with irregular terminations, and rarely terminated by a low-angle pyramid. The mineral is orange brown to red brown, streak is beige, and luster is vitreous, translucent to transparent. Fracture is irregular. In thin section, it is orange brown. The mineral is optically biaxial (–) with α 1.805(5), β 1.825(5), γ 1.8305(5) (white light); 2Vmeas 58(5)°, 2Vcalc 54.7°; optical orientation X = c, Y = b, Z = a. Dispersion is very strong, r > v. Pleochroism is strong with X orange yellow, Y red brown, Z red brown; X << Z < Y. It is unreactive in concentrated HCl at room temperature. Thirteen chemical analyses by WDS-EMPA gave the following empirical formula (based on 24 O apfu): (Ba0.69Ca1.25Mn2+0.70Sr0.21Na0.12Mg0.02)Σ2.99(Mn3+3.97Al0.03)Σ4(Si3O10)(Si2O7)(OH)3.87·3.13H2O. The mineral is orthorhombic, space group Amm2, with unit-cell parameters a 16.312(8), b 6.176(4), c 9.075(6) Å, V 914.2(10) Å3, and Z = 2. The seven strongest X-ray powder diffraction lines are [d Å (I%; hkl)]: 16.21 (49; 100), 4.86 (44; 111), 4.34 (56; 102,211), 2.871 (54; 220), 2.731 (100; 511,013), 2.671 (74; 320,113,502), and 2.426 (51; 222,313,611). The crystal structure (R1 = 0.0572 for 1485 reflections with I > 2σI) is based on straight edge-sharing chains of Mn3+-centered octahedra extending along [010], which are bridged by disilicate (Si2O7) and trisilicate (Si3O10) groups, yielding a framework. Cavities within this framework contain two large cation sites. The structure of demagistrisite can be considered transitional between the structures of orientite and noelbensonite. Demagistrisite is named in honor of Leandro de Magistris (1906–1990).

Oxyplumboroméite, Pb2Sb2O7, a new mineral species of the pyrochlore supergroup from Harstigen mine, Värmland, Sweden

2013 ◽  
Vol 77 (7) ◽  
pp. 2931-2939 ◽  
Author(s):  
U. Hålenius ◽  
F. Bosi
Keyword(s):  
Crystal Structure ◽  
Structure Refinement ◽  
New Mineral ◽  
Crystal Structure Refinement ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
X Ray ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Mohs Hardness

AbstractOxyplumboroméite, Pb2Sb2O7, is a new mineral of the roméite group of the pyrochlore supergroup (IMA 2013-042). It is found together with calcite and leucophoenicite in fissure fillings in tephroite skarn at the Harstigen mine, Värmland, Sweden. The mineral occurs as yellow to brownish yellow rounded grains or imperfect octahedra. Oxyplumboroméite has a Mohs hardness of ∼5, a calculated density of 6.732 g/cm3 and is isotropic with a calculated refractive index of 2.061. Oxyplumboroméite is cubic, space group Fdm, with the unit-cell parameters a = 10.3783(6) Å, V = 1117.84(11) Å3 and Z = 8. The strongest five X-ray powder-diffraction lines [d in Å(I)(hkl)] are: 2.9915(100)(222), 2.5928(32)(400), 1.8332(48)(440), 1.5638(38)(622) and 1.1900(12)(662). The crystal structure of oxyplumboroméite was refined to an R1 index of 3.02% using 160 unique reflections collected with MoKα radiation. Electron microprobe analyses in combination with crystal-structure refinement, infrared, Mössbauer and electronic absorption spectroscopy resulted in the empirical formula A(Pb0.92Ca0.87Mn0.09Sr0.01Na0.05)Σ1.93B(Sb1.73Fe3+0.27)Σ2.00X+Y[O6.64(OH)0.03]Σ6.67. Oxyplumboroméite is the Pb analogue of oxycalcioroméite, ideally Ca2Sb2O7.

scholarly journals Isselite, Cu6(SO4)(OH)10(H2O)4⋅H2O, a new mineral species from Eastern Liguria, Italy

2020 ◽  
Vol 84 (5) ◽  
pp. 653-661
Author(s):  
Cristian Biagioni ◽  
Donato Belmonte ◽  
Cristina Carbone ◽  
Roberto Cabella ◽  
Nicola Demitri ◽  
...  
Keyword(s):  
New Mineral ◽  
Optical Orientation ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Light Blue ◽  
X Ray ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Mining Complex

AbstractThe new mineral isselite, Cu6(SO4)(OH)10(H2O)4⋅H2O, has been discovered in the Lagoscuro mine, Monte Ramazzo mining complex, Genoa, Eastern Liguria, Italy. It occurs as sprays of blue acicular crystals, up to 0.1 mm long, associated with brochantite and posnjakite. Streak is light blue and the lustre is vitreous. Isselite is brittle, with irregular fracture and good cleavage on {001} and {100}. Measured density is 3.00(2) g/cm3. Isselite is optically biaxial (–), with α = 1.599(2), β = 1.633(2) and γ = 1.647(2) (determined in white light). The measured 2V is 63.6(5)°. Dispersion is moderate, with r > v. The optical orientation is X = b, Y = c and Z = a. Isselite is pleochroic, with X = light blue, Y = blue, Z = blue; X << Z < Y. Electron microprobe analyses give (wt.%): SO3 11.45(21), MgO 0.31(7), CoO 1.07(14), NiO 9.41(90), CuO 51.29(126), ZnO 1.10(20), H2Ocalc 24.21, total 98.84. The empirical formula of isselite, based on Σ(Mg,Co,Ni,Cu,Zn) = 6 atoms per formula unit, is (Cu4.80Ni0.94Co0.11Zn0.10Mg0.06)Σ6.00(S1.06O4.19)(OH)10⋅5H2O. Isselite is orthorhombic, space group Pmn21, with unit-cell parameters a = 6.8070(14), b = 5.8970(12), c = 20.653(4) Å, V = 829.0(3) Å3 and Z = 2. The crystal structure of isselite was refined from single-crystal X-ray diffraction data to R1 = 0.067 on the basis of 2964 reflections with Fo > 4σ(Fo). It shows a layered structure formed by zig-zag {001} layers of Cu-centred polyhedra. Sulfate groups occur in the interlayer along with one H2O group. Isselite is chemically related to redgillite and montetrisaite.

Twinning and incommensurate modulation in baumoite, Ba0.5[(UO2)3O8Mo2(OH)3](H2O)~3, the first natural Ba uranyl molybdate

2019 ◽  
Vol 83 (4) ◽  
pp. 507-514
Author(s):  
Peter Elliott ◽  
Jakub Plášil ◽  
Václav Petříček ◽  
Jiří Čejka ◽  
Luca Bindi
Keyword(s):  
South Australia ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
X Ray ◽  
Cell Parameters ◽  
Orange Yellow ◽  
Incommensurate Modulation ◽  
Mohs Hardness

ABSTRACTBaumoite, Ba0.5[(UO2)3O8Mo2(OH)3](H2O)~3, is a new mineral found near Radium Hill, South Australia, where it occurs in a granite matrix associated with baryte, metatorbernite, phurcalite and kaolinite. Baumoite forms thin crusts of yellow to orange–yellow tabular to prismatic crystals. The mineral is translucent with a vitreous lustre and pale yellow streak. Crystals are brittle, the fracture is uneven and show one excellent cleavage. The Mohs hardness is ~2½. The calculated density is 4.61 g/cm3. Optically, baumoite crystals are biaxial (–), with α = 1.716(4), β = 1.761(4), γ = 1.767(4) (white light); and 2Vcalc= 42.2°. Electron microprobe analyses gave the empirical formula Ba0.87Ca0.03Al0.04U2.97Mo2.02P0.03O22H11.99, based on 22 O atoms per formula unit. The eight strongest lines in the powder X-ray diffraction pattern are [dobsÅ (I) (hkl)]: 9.175(39)(12${\bar 1}$), 7.450(100)(020), 3.554(20)(221), 3.365(31)(004, 202), 3.255(31)(123, 30${\bar 2}$), 3.209(28)(12${\bar 4}$), 3.067(33)(30${\bar 3}$, 222, 32${\bar 2}$) and 2.977(20)(142). Single-crystal X-ray studies (R1= 5.85% for 1892 main reflections) indicate that baumoite is monoclinic, superspace groupX2/m(a0g)0swithX= (0,½,0,½), with unit-cell parameters:a= 9.8337(3),b= 15.0436(5),c= 14.2055(6) Å, β = 108.978(3)°,V= 1987.25(13) Å3andZ= 4. The crystal structure is twinned and incommensurately modulated and is based upon sheets of U6+and Mo6+polyhedra of unique topology. Four independent cationic sites partially occupied by Ba atoms are located between the sheets, together with H2O molecules.

Brumadoite, a new copper tellurate hydrate, from Brumado, Bahia, Brazil

2008 ◽  
Vol 72 (6) ◽  
pp. 1201-1205 ◽  
Author(s):  
D. Atencio ◽  
A. C. Roberts ◽  
P. A. Matioli ◽  
J. A. R. Stirling ◽  
K. E. Venance ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Infrared Spectra ◽  
Coarse Grained ◽  
New Mineral ◽  
Unit Cell Parameters ◽  
Quartz Crystals ◽  
X Ray ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Spot Tests

AbstractBrumadoite, ideally Cu3Te6+O4(OH)4-5H2O, is a new mineral from Pedra Preta mine, Serra das Eguas. Brumado, Bahia, Brazil. It occurs as microcrystalline aggregates both on and, rarely, pseudomorphous after coarse-grained magnesite, associated with mottramite and quartz. Crystals are platy, subhedral. 1—2 μm in size. Brumadoite is blue (near RHS 114B), has a pale blue streak and a vitreous lustre. It is transparent to translucent and does not fluoresce. The empirical formula is (Cu2.90Pb0.04Ca0.01)Σ2.95 (Te0.936+Si0.05)Σ0.98O3.92(OH)3.84.5.24H2O. Infrared spectra clearly show both (OH) and H2O. Microchemical spot tests using a KI solution show that brumadoite has tellurium in the 6+ state. The mineral is monoclinic, P2/m or P21. Unit-cell parameters refined from X-ray powder data are a 8.629(2) Å, b 5.805(2) Å, c 7.654(2) Å,β 0 103.17(2)°, F 373.3(2) Å3, Z= 2. The eight strongest X-ray powder-diffraction lines [d in Å,(I),(hkl)] are: 8.432,(100),(100); 3.162,(66),(2̄02); 2.385,(27),(220); 2.291,(12),(l̄22); 1.916,(11),(312); 1.666,(14),(4̄22,114); 1.452,(10),(323,040); 1.450,(10),(422,403). The name is for the type locality, Brumado, Bahia, Brazil. The new mineral species has been approved by the CNMNC (IMA 2008-028).

Arrheniusite-(Ce), CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11, a New Member of the Vicanite Group, from the Östanmossa Mine, Norberg, Sweden

2021 ◽  
Author(s):  
Dan Holtstam ◽  
Luca Bindi ◽  
Paola Bonazzi ◽  
Hans-Jürgen Förster ◽  
Ulf B. Andersson
Keyword(s):  
Structure Refinement ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Epma Data ◽  
X Ray ◽  
Cell Parameters ◽  
Greenish Yellow ◽  
The Ideal

ABSTRACT Arrheniusite-(Ce) is a new mineral (IMA 2019-086) from the Östanmossa mine, one of the Bastnäs-type deposits in the Bergslagen ore region, Sweden. It occurs in a metasomatic F-rich skarn, associated with dolomite, tremolite, talc, magnetite, calcite, pyrite, dollaseite-(Ce), parisite-(Ce), bastnäsite-(Ce), fluorbritholite-(Ce), and gadolinite-(Nd). Arrheniusite-(Ce) forms anhedral, greenish-yellow translucent grains, exceptionally up to 0.8 mm in diameter. It is optically uniaxial (–), with ω = 1.750(5), ε = 1.725(5), and non-pleochroic in thin section. The calculated density is 4.78(1) g/cm3. Arrheniusite-(Ce) is trigonal, space group R3m, with unit-cell parameters a = 10.8082(3) Å, c = 27.5196(9) Å, and V = 2784.07(14) Å3 for Z = 3. The crystal structure was refined from X-ray diffraction data to R1 = 3.85% for 2286 observed reflections [Fo &gt; 4σ(Fo)]. The empirical formula for the fragment used for the structural study, based on EPMA data and results from the structure refinement, is: (Ca0.65As3+0.35)Σ1(Mg0.57Fe2+0.30As5+0.10Al0.03)Σ1[(Ce2.24Nd2.13La0.86Gd0.74Sm0.71Pr0.37)Σ7.05(Y2.76Dy0.26Er0.11Tb0.08Tm0.01Ho0.04Yb0.01)Σ3.27Ca4.14]Σ14.46(SiO4)3[(Si3.26B2.74)Σ6O17.31F0.69][(As5+0.65Si0.22P0.13)Σ1O4](B0.77O3)F11; the ideal formula obtained is CaMg[(Ce7Y3)Ca5](SiO4)3(Si3B3O18)(AsO4)(BO3)F11. Arrheniusite-(Ce) belongs to the vicanite group of minerals and is distinct from other isostructural members mainly by having a Mg-dominant, octahedrally coordinated site (M6); it can be considered a Mg-As analog to hundholmenite-(Y). The threefold coordinated T5 site is partly occupied by B, like in laptevite-(Ce) and vicanite-(Ce). The mineral name honors C.A. Arrhenius (1757–1824), a Swedish officer and chemist, who first discovered gadolinite-(Y) from the famous Ytterby pegmatite quarry.

Liudongshengite, Zn4Cr2(OH)12(CO3)·3H2O, a new mineral of the hydrotalcite supergroup, from the 79 mine, Gila County, Arizona, USA

2021 ◽  
Vol 59 (4) ◽  
pp. 763-769
Author(s):  
Hexiong Yang ◽  
Ronald B. Gibbs ◽  
Cody Schwenk ◽  
Xiande Xie ◽  
Xiangping Gu ◽  
...  
Keyword(s):  
Unit Cell ◽  
New Mineral ◽  
Unit Cell Parameters ◽  
Cell Parameters ◽  
New Mineral Species ◽  
General Chemical ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
Trivalent Cations ◽  
Positively Charged

ABSTRACT A new mineral species, liudongshengite, ideally Zn4Cr2(OH)12(CO3)·3H2O, has been found in the 79 mine, Gila County, Arizona, USA. It occurs as micaceous aggregates or hexagonal platy crystals (up to 0.10 × 0.10 × 0.01 mm). The mineral is pinkish and transparent with white streak and vitreous luster. It is brittle and has a Mohs hardness of ∼1.5, with perfect cleavage on (001). No twinning or parting is observed macroscopically. The measured and calculated densities are 2.95 (3) and 3.00 g/cm3, respectively. Optically, liudongshengite is uniaxial (−), with ω = 1.720 (8), ε = 1.660 (7) (white light). An electron microprobe analysis, combined with the carbon content measured using an elemental combustion system equipped with mass spectrometry, yielded the empirical formula (Zn3.25Mg0.17Cr2.58)Σ6.00(OH)12(CO3)1.29·3H2O, based on (M2+ + M3+) = 6 apfu, where M2+ and M3+ are divalent and trivalent cations, respectively. Liudongshengite belongs to the quintinite group within the hydrotalcite supergroup and is the Cr-analogue of zaccagnaite-3R, Zn4Al2(OH)12(CO3)·3H2O. It is trigonal, with space group Rm and unit-cell parameters a = 3.1111(4), c = 22.682(3) Å, and V = 190.12(4) Å3. The crystal structure of liudongshengite is composed of positively charged brucite-like layers, [M2+1–xM3+x(OH)2]x+, alternating with negatively charged layers of (CO3)2–·3H2O. Compared to other minerals in the quintinite group, liudongshengite is remarkably enriched in M3+, with an M2+:M3+ ratio of 1.33:1. Like zaccagnaite-3R and many other hydrotalcite-type minerals, liudongshengite may also possess polytypes, as a series of synthetic hydrotalcite-type compounds with a general chemical formula [Zn4Cr2(OH)12]X2·4H2O, where X = Cl–, NO3–, or ½ SO42–, but with unit-cell parameters different from those for liudongshengite, have been reported previously.

Müllerite, the Fe-analogue of backite from Otto Mountain, California, USA

2020 ◽  
Vol 58 (4) ◽  
pp. 413-419
Author(s):  
Stuart J. Mills ◽  
Anthony R. Kampf ◽  
Koichi Momma ◽  
Robert M. Housley ◽  
Joseph Marty
Keyword(s):  
Rietveld Analysis ◽  
Thin Plates ◽  
New Mineral ◽  
San Bernardino County ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Cell Parameters ◽  
San Bernardino ◽  
Perfect Cleavage ◽  
Reddish Orange

ABSTRACT Müllerite (IMA2019–060) is a new mineral found at several workings on Otto Mountain, 2.5 km NW of Baker, San Bernardino County, California, USA. Müllerite occurs as hexagonal tablets and thin plates up to 0.2 mm across, intergrown ball-like clusters, and scattered flakes. Crystals are yellow, tending to reddish-orange, and have a pale-yellow streak and subadamantine to greasy luster. Crystals are brittle with an irregular fracture and have a hardness of ∼2 and perfect cleavage on {001}. The main forms observed are {100} and {001}. The calculated density is 5.812 g/cm3. The empirical formula (based on 7 O + Cl + I apfu) is Pb1.83Ag0.26Fe0.93Al0.03Cu0.02Te6+0.95O5.56Cl1.30I0.14; the endmember formula is Pb2Fe3+(Te6+O6)Cl. Müllerite is trigonal, space group P312, with the unit cell parameters a = 5.2040(5), c = 8.9654(12) Å, V = 210.23(3) Å3, and Z = 1. The crystal structure of müllerite was refined using Rietveld analysis and converged to Rwp = 4.861%, S = 0.1873, RB = 1.800%, and RF = 0.691%. Müllerite is the Fe-analogue of backite, Pb2Al3+(Te6+O6)Cl.

Sign in / Sign up

Export Citation Format

Share Document