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.

Meieranite, Na2Sr3MgSi6O17, a New Mineral from the Wessels Mine, Kalahari Manganese Fields, South Africa

2019 ◽  
Vol 57 (4) ◽  
pp. 457-466 ◽  
Author(s):  
Hexiong Yang ◽  
Xiangping Gu ◽  
Robert T. Downs ◽  
Stanley H. Evans ◽  
Jaco J. Van Nieuwenhuizen ◽  
...  
Keyword(s):  
South Africa ◽  
Empirical Formula ◽  
Microprobe Analysis ◽  
New Mineral ◽  
Cell Parameters ◽  
New Mineral Species ◽  
General Chemical ◽  
Northern Cape ◽  
Coupled Substitution ◽  
Mohs Hardness

Abstract A new mineral species, meieranite, ideally Na2Sr3MgSi6O17, has been found in the Wessels mine, Kalahari Manganese Fields, Northern Cape Province, South Africa. It occurs in isolated aggregates embedded in a matrix mainly of sugilite, along with minor aegirine and pectolite. Crystals of meieranite are up to 0.5 × 0.5 × 0.4 mm in size. No twinning is observed. The mineral is light blue to blue in transmitted and under incident lights, transparent with white streak, and has vitreous luster. It is brittle and has a Mohs hardness of 5.5; cleavage is good on {010} and no parting was observed. The measured and calculated densities are 3.41(3) and 3.410 g/cm3, respectively. Optically, meieranite is biaxial (–), with α = 1.610(1), β = 1.623(1), γ = 1.630(1) (white light), 2V (meas.) = 70(1)°, 2V (calc.) = 72°. The calculated compatibility index based on the empirical formula is –0.007 (superior). An electron microprobe analysis yields an empirical formula (based on 17 O apfu) of Na1.96(Sr2.91Ba0.03Ca0.03Pb0.02)Σ2.99(Mg0.62Mn0.28Co0.07Fe0.01)Σ0.98Si6.03O17, which can be simplified to Na2Sr3MgSi6O17. Meieranite is orthorhombic, with space group P21nb and unit-cell parameters a 7.9380(2), b 10.4923(3), c 18.2560(6) Å, and V 1520.50(8) Å3. Its crystal structure is characterized by two kinds of layers that alternate along [010]: layers of corner-sharing SiO4 and M2+O4 tetrahedra (M2+ = Mg, Mn, Co, Fe) and layers of NaO6 and SrO8 polyhedra. The tetrahedral layers consist of eight-, five-, and four-membered rings and are composed of [Si6O17] ribbons (parallel to [101]) linked together by MO4 tetrahedra. Most remarkably, the structure of meieranite is topologically identical to that of the nordite group of minerals, which has the general chemical formula Na3SrR3+M2+Si6O17, where R = Ce and La and M = Zn, Fe, and Mn. Accordingly, chemically, meieranite may be obtained through the coupled substitution of 2Sr2+ for (Na+ + R3+) in nordite.

Wesselsite, SrCu[Si4O10], a further new gillespite-group mineral from the Kalahari Manganese Field, South Africa

1996 ◽  
Vol 60 (402) ◽  
pp. 795-798 ◽  
Author(s):  
G. Giester ◽  
B. Rieck
Keyword(s):  
South Africa ◽  
New Mineral ◽  
Solid Solution Series ◽  
Blue Colour ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Light Blue ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Perfect Cleavage

AbstractWesselsite, SrCu[Si4O10], is a new mineral species from the Wessels mine, Kalahari Manganese Field, South Africa, and it belongs to the gillespite group. Wesselsite is tetragonal, space group P4/ncc; the unit cell parameters, refined from Gandolfi film data, are a = 7.366(1), c = 15.574(3) Å V = 845.01 Å3. The strongest lines are (dobs/lobs/hkl) (7.79/35/002), (4.33/20/112), (3.89/20/004), (3.44/40/104), (3.33/100/202), (3.12/55/114), (3.03/50/212), (2.68/25/204), (2.61/30/220) and (2.32/30/116). Wesselsite is associated with hennomartinite, embedded in a matrix of sugilite, xonotlite, quartz and pectolite. Microprobe analyses of 111 samples show that it is the end-member of a solid solution series with effenbergerite, BaCu[Si4O10], with substitutions of Sr by Ba up to 50 mol.%. Wesselsite forms tiny subhedral plates in sizes not exceeding 50 × 50 × 5 µm, arranged in clusters of up to 200 µm. It shows a perfect cleavage parallel to {001}, has blue colour, white to light blue streak, and is uniaxial negative with ω = 1.630(2), ε = 1.590(5), strongly pleochroic from blue (ω) to pale blue (ε). The calculated density is 3.32 g cm−3, the measured density is 3.2(1) g cm−3.

Ferrobobfergusonite, □Na2Fe2+5Fe3+Al(PO4)6, a New Mineral of the Bobfergusonite Group from the Victory Mine, Custer County, South Dakota, USA

2021 ◽  
Author(s):  
Hexiong Yang ◽  
Tommy Yong ◽  
Robert T. Downs
Keyword(s):  
South Dakota ◽  
Empirical Formula ◽  
New Mineral ◽  
Cell Parameters ◽  
Coordination Numbers ◽  
New Mineral Species ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
Custer County ◽  
Deep Green

ABSTRACT A new mineral species, ferrobobfergusonite, ideally □Na2Fe2+5Fe3+Al(PO4)6, has been found in the Victory Mine, Custer County, South Dakota, USA. It is massive and associated with ferrowyllieite, schorl, fillowite, arrojadite, quartz, and muscovite. Broken pieces of ferrobobfergusonite are blocky or tabular with single crystals up to 0.9 × 0.7 × 0.4 mm. No twinning or parting is observed macroscopically. The mineral is deep green-brown and transparent with a pale green-yellow streak and vitreous luster. It is brittle and has a Mohs hardness of ∼5, with perfect cleavage on {010}. The measured and calculated densities are 3.68(1) and 3.69 g/cm3, respectively. Optically, ferrobobfergusonite is biaxial (+), with α = 1.698 (2), β = 1.705 (2), γ = 1.727 (2) (white light), 2V (meas.) = 65(2)°, 2V (calc.) = 60°, with orientation of the optic axes α ∧ X = 16°, β = Y, with X = yellowish brown, Y = brown, and Z = deep brown. The dispersion is very strong with r > v. The calculated compatibility index based on the empirical formula is 0.017 (superior). An electron microprobe analysis yielded an empirical formula (based on 24 O apfu) of (Na1.72□1.28)Σ3.00(Fe2+3.50Mn0.89Mg0.44Ca0.13)Σ4.96(Fe3+0.77Al0.23)Σ1.00Al(PO4)6. Ferrobobfergusonite is isostructural with bobfergusonite, a member of the alluaudite supergroup. It is monoclinic, with space group P21/n and unit-cell parameters a = 12.7156(3), b = 12.3808(3), c = 10.9347(3) Å, β = 97.3320(10)°, and V = 1707.37(7) Å3. The crystal structure of ferrobobfergusonite contains six octahedral M (= Fe2+, Mg, Mn2+, Al, Fe3+) sites and five X (= Na, Mn2+, Ca) sites with coordination numbers between 6 and 8. The six MO6 octahedra share edges to form two types of kinked chains extending along [101], with one consisting of M1–M4–M5 linkages and the other of M2–M3–M6 linkages. These chains are joined by PO4 tetrahedra to form sheets parallel to (010), which are linked together through corner-sharing between PO4 tetrahedra and MO6 octahedra in the adjacent sheets, leaving open channels parallel to a, where the large X cations are situated. The M cations are strongly ordered over the six sites, with M1, M2, M3, and M4 being dominantly occupied by Fe2+, and M5 and M6 by Fe3+ and Al, respectively. Among the five X sites, the X1 site is filled with Mn2+ and Ca, whereas the X2–X5 sites are partially occupied by Na.

Taniajacoite and Strontioruizite, Two New Minerals Isostructural with Ruizite from the N'Chwaning III Mine, Kalahari Manganese Field, South Africa

2021 ◽  
Author(s):  
Hexiong Yang ◽  
Xiangping Gu ◽  
Bruce Cairncross ◽  
Robert T. Downs ◽  
Stanley H. Evans
Keyword(s):  
South Africa ◽  
White Light ◽  
Empirical Formula ◽  
Unit Cell ◽  
New Mineral ◽  
Space Group ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Mohs Hardness ◽  
Cell Volumes

ABSTRACT Two new mineral species, taniajacoite and strontioruizite, ideally SrCaMn3+2Si4O11(OH)4·2H2O and Sr2Mn3+2Si4O11(OH)4·2H2O, respectively, have been identified from the N'Chwaning III mine, Kalahari manganese field, South Africa. Both minerals occur as brown radiating groups or aggregates of acicular or prismatic crystals, with individual crystals up to 0.15 × 0.04 × 0.02 mm for taniajacoite and 1.3 × 0.2 × 0.2 mm for strontioruizite. Minerals associated with taniajacoite include sugilite, aegirine, pectolite, richterite, potassic-ferri-leakeite, and lipuite, whereas those associated with strontioruizite include sugilite, potassic-magnesio-arfvedsonite, and lipuite. Both taniajacoite and strontioruizite are brown in transmitted light, transparent with very light brown streak and vitreous luster. They are brittle and have a Mohs hardness of 5–5.5; cleavage is good on {010} and no parting or twinning is observed macroscopically. The measured and calculated densities are 3.05(2) and 3.09 g/cm3, respectively, for taniajacoite and 3.20(2) and 3.16 g/cm3 for strontioruizite. Optically, both taniajacoite and strontioruizite are biaxial (–), with α = 1.686(2), β = 1.729(2), γ = 1.746(2) (white light), 2V (meas.) = 63.7(5)°, 2V (calc.) = 62.5° for the former and α = 1.692(2), β = 1.734(2), γ = 1.747(2) (white light), 2V (meas.) = 59.1(5)°, 2V (calc.) = 56.6° for the latter. The calculated compatibility index based on the empirical formula is 0.008 for taniajacoite and 0.015 for strontioruizite. An electron microprobe analysis yielded an empirical formula (based on 17 O apfu) of Sr(Ca0.81Sr0.19)Σ1.00(Mn3+1.90Fe3+0.15Al0.01)Σ2.06Si3.96O11(OH)4·2H2O for taniajacoite and (Sr1.61Ca0.42)Σ2.03(Mn3+1.95Fe3+0.05)Σ2.00Si3.98O11(OH)4·2H2O for strontioruizite. Taniajacoite and strontioruizite are isostructural with ruizite. Strontioruizite, like ruizite, is monoclinic with space group C2 and unit-cell parameters a = 9.1575(4), b = 6.2857(4), c = 12.0431(6) Å, β = 91.744(4)°, and V = 692.90(6) Å3, whereas taniajacoite is triclinic, with space group C1 and a = 9.1386(5), b = 6.2566(3), c = 12.0043(6) Å, α = 90.019(4), β = 91.643(4), γ = 89.900(4)°, and V = 686.08(6) Å3. Their structures are characterized by chains of edge-sharing MnO6 octahedra extended along [010], which are linked together by corner-shared SiO4 tetrahedra in four-membered [Si4O11(OH)2] linear clusters, giving rise to a so-called “hetero-polyhedral framework”. The large cations Sr2+ and Ca2+ occupy the seven-coordinated interstices. Unlike monoclinic ruizite and strontioruizite, taniajacoite with Sr:Ca ≈ 1:1 is triclinic, owing to the ordering of Sr2+ and Ca2+ into two crystallographically distinct sites, indicating an incomplete solid solution between Ca and Sr endmembers. The unit-cell volumes for ruizite, taniajacoite, and strontioruizite appear to vary linearly with the Sr/(Ca + Sr) ratio.

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.

Kingstonite, (Rh,Ir,Pt)3S4, a new mineral species from Yubdo, Ethiopia

2005 ◽  
Vol 69 (4) ◽  
pp. 447-453 ◽  
Author(s):  
C. J. Stanley ◽  
A. J. Criddle ◽  
J. Spratt ◽  
A. C. Roberts ◽  
J. T. Szymański ◽  
...  
Keyword(s):  
Empirical Formula ◽  
Unit Cell ◽  
New Mineral ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Cell Parameters ◽  
New Mineral Species ◽  
Reflected Light ◽  
Grey Colour ◽  
Reflectance Data

AbstractKingstonite, ideally Rh3S4, is a new mineral from the Bir Bir river, Yubdo District, Wallaga Province, Ethiopia. It occurs as subhedral, tabular elongate to anhedral inclusions in a Pt-Fe nugget with the associated minerals isoferroplatinum, tetraferroplatinum, a Cu-bearing Pt-Fe alloy, osmium, enriched oxide remnants of osmium, laurite, bowieite, ferrorhodsite and cuprorhodsite. It is opaque with a metallic lustre, has a black streak, is brittle and has a subconchoidal fracture and a good cleavage parallel to [001]. VHN25 is 871–920 kg/mm2. In plane-polarized reflected light, kingstonite is a pale slightly brownish grey colour. It is weakly pleochroic and displays a weak bireflectance. It does not possess internal reflections. The anisotropy is weak to moderate in dull greys and browns. Reflectance data and colour values are tabulated. Average results of twenty electron microprobe analyses on four grains give Rh 46.5, Ir 16.4, Pt 11.2, S 25.6, total 99.7 wt.%. The empirical formula is (Rh2.27Ir0.43Pt0.29)Σ2.99S4.01, based on 7 atoms per formula unit (a.p.f.u.). Kingstonite is monoclinic (C2/m) with a = 10.4616(5), b = 10.7527(5), c = 6.2648(3) Å, β = 109.000(5)°, V = 666.34(1) Å3 (Z = 6). The calculated density is 7.52 g/cm3 (on the basis of the empirical formula and unit-cell parameters refined from powder data). The seven strongest X-ray powder-diffraction lines [d in Å(I) (hkl)] are: 3.156 (100) (310), 3.081 (100) (1̄31), 2.957 (90) (002), 2.234 (60) (202), 1.941 (50) (2̄23), 1.871 (80) (4̄41) and 1.791 (90) (060, 1̄33). The structure of kingstonite was solved and refined to Rp = 3.8%. There are four distinct metal sites with Rh occupancies of 0.64–0.89. Two metal sites are regular RhS6 octahedra that share edges to form a ribbon running parallel to c. The other two metal sites are coordinated by 4 S + 2 Rh and 5 S + 2 Rh and define a puckered Rh6 ring. The ribbons of regular RhS6 octahedra alternate with the columns of Rh6 rings linked by S atoms. S–S bridges also connect the ribbons and columns. As such, the kingstonite structure is essentially that of synthetic Rh3S4. Minor differences in the unit-cell parameters, atom coordinates and displacement parameters of kingstonite and synthetic Rh3S4 arise from the considerable substitution of Ir for Rh. The mineral name honours Gordon Kingston (formerly of Cardiff University) in recognition of his contributions to platinum group element mineralogy and the geology of their mineral deposits.

Minjiangite, BaBe2(PO4)2, a new mineral from Nanping No. 31 pegmatite, Fujian Province, southeastern China

2015 ◽  
Vol 79 (5) ◽  
pp. 1195-1202 ◽  
Author(s):  
C. Rao ◽  
F. Hatert ◽  
R. C. Wang ◽  
X. P. Gu ◽  
F. Dal Bo ◽  
...  
Keyword(s):  
Unit Cell ◽  
Powder Xrd ◽  
New Mineral ◽  
Unit Cell Parameters ◽  
Southeastern China ◽  
Fujian Province ◽  
Calculated Density ◽  
Xrd Pattern ◽  
Cell Parameters ◽  
New Mineral Species

AbstractMinjiangite, ideally BaBe2(PO4)2, is a new mineral species which has been found in the Nanping No. 31 pegmatite, Fujian Province, southeastern China. It occurs in the fractures of montebrasite from pegmatite zone IV, and is associated with quartz, muscovite, hydroxylapatite and palermoite. Minjiangite forms subhedral to euhedral white crystals from 5 to 200 μm long, transparent to translucent, with a vitreous lustre. The estimated Mohs hardness is ∼6, the tenacity is brittle and no cleavage was observed. The calculated density is 3.49 g/cm3. Optically, minjiangite is uniaxial (+), with ω = 1.587(3), ε = 1.602(2) (λ = 589 nm). Electron-microprobe analyses (average of 8) give P2O5 40.16, BaO 43.01, BeO 14.06 (measured by Secondary Ion Mass Spectrometry), SiO2 0.17, CaO 0.17, SrO 0.08, FeO 0.03, MgO 0.01, TiO2 0.07, K2O 0.05, Na2O 0.11, total 97.92 wt.%. The empirical formula, calculated on the basis of 8 O a.p.f.u., is (Ba0.99Ca0.01Na0.01)Σ1.01Be1.98(P1.99Si0.01)Σ2.00O8. The powder X-ray diffraction (XRD) pattern of minjiangite perfectly fits that of synthetic BaBe2(PO4)2; the strongest eight lines of the powder XRD pattern of the natural phosphate [d in Å (I)(hkl)] are: 3.763(100)(101); 2.836(81.3)(102); 2.515(32.3)(110); 2.178(25.6)(200); 2.1620(19)(103); 2.090(63.9)(201); 1.770(16.2)(113); 1.507(25.4)(212). Unit-cell parameters, refined from the powder XRD pattern of natural minjiangite, are a = 5.030(8), c = 7.467 (2) Å, V = 163.96(3) Å3. These unit-cell parameters confirm that minjiangite is the natural analogue of synthetic BaBe2(PO4)2(P6/mmm, a = 5.029(1), c = 7.466 (1) Å, V = 163.52(1) Å3, Z = 1); its crystal structure is topologically similar to that of dmisteinbergite, CaAl2Si2O8, a hexagonal polymorph of anorthite. The formation of minjiangite is related to the hydrothermal alteration of montebrasite by late Ba- and Be-rich fluids.

scholarly journals Bluebellite and mojaveite, two new minerals from the central Mojave Desert, California, USA

2014 ◽  
Vol 78 (5) ◽  
pp. 1325-1340 ◽  
Author(s):  
S. J. Mills ◽  
A. R. Kampf ◽  
A. G. Christy ◽  
R. M. Housley ◽  
G. R. Rossman ◽  
...  
Keyword(s):  
Empirical Formula ◽  
Mojave Desert ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Calculated Density ◽  
Cell Parameters ◽  
Bluish Green ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
Greenish Blue

AbstractBluebellite, Cu6[I5+O3(OH)3](OH)7Cl and mojaveite, Cu6[Te6+O4(OH)2](OH)7Cl, are new secondary copper minerals from the Mojave Desert. The type locality for bluebellite is the D shaft, Blue Bell claims, near Baker, San Bernardino County, California, while cotype localities for mojaveite are the E pit at Blue Bell claims and also the Bird Nest drift, Otto Mountain, also near Baker. The two minerals are very similar in their properties. Bluebellite is associated particularly with murdochite, but also with calcite, fluorite, hemimorphite and rarely dioptase in a highly siliceous hornfels. It forms bright bluishgreen plates or flakes up to ~20 mm 620 mm 65 mm in size that are usually curved. The streak is pale bluish green and the lustre is adamantine, but often appears dull because of surface roughness. It is non-fluorescent. Bluebellite is very soft (Mohs hardness ~1), sectile, has perfect cleavage on {001} and an irregular fracture. The calculated density based on the empirical formula is 4.746 g cm–3. Bluebellite is uniaxial (–), with mean refractive index estimated as 1.96 from the Gladstone-Dale relationship. It is pleochroic O (bluish green) >> E (nearly colourless). Electron microprobe analyses gave the empirical formula Cu5.82I0.99Al0.02Si0.12O3.11(OH)9.80Cl1.09based on 14 (O+Cl) a.p.f.u. The Raman spectrum shows strong iodate-related bands at 680, 611 and 254 cm–1. Bluebellite is trigonal, space group R3, with the unit-cell parameters: a = 8.3017(5), c = 13.259(1) Å , V = 791.4(1) Å 3 and Z = 3. The eight strongest lines in the powder X-ray diffraction (XRD) pattern are [dobs/Å (I) (hkl)]: 4.427(99)(003), 2.664(35)(211), 2.516(100)(212̄ ), 2.213(9)(006), 2.103(29)(033,214), 1.899(47)(312,215̄ ), 1.566(48)(140,217) and 1.479(29)(045,143̄ ,324).Mojaveite occurs at the Blue Bell claims in direct association with cerussite, chlorargyrite, chrysocolla, hemimorphite, kettnerite, perite, quartz and wulfenite, while at the Bird Nest drift, it is associated with andradite, chrysocolla, cerussite, burckhardtite, galena, goethite, khinite, mcalpineite, thorneite, timroseite, paratimroseite, quartz and wulfenite. It has also been found at the Aga mine, Otto Mountain, with cerussite, chrysocolla, khinite, perite and quartz. Mojaveite occurs as irregular aggregates of greenish-blue plates flattened on {001} and often curved, which rarely show a hexagonal outline, and also occurs as compact balls, from sky blue to medium greenish blue in colour. Aggregates and balls are up to 0.5 mm in size. The streak of mojaveite is pale greenish blue, while the lustre may be adamantine, pearly or dull, and it is non-fluorescent. The Mohs hardness is ~1. It is sectile, with perfect cleavage on {001} and an irregular fracture. The calculated density is 4.886 g cm–3, based on the empirical formulae and unit-cell dimensions. Mojaveite is uniaxial (–), with mean refractive index estimated as 1.95 from the Gladstone-Dale relationship. It is pleochroic O (greenish blue) >> E (light greenish blue). The empirical formula for mojaveite, based on 14 (O+Cl) a.p.f.u., is Cu5.92Te1.00Pb0.08Bi0.01O4(OH)8.94Cl1.06. The most intense Raman bands occur at 694, 654 (poorly resolved), 624, 611 and 254 cm–1. Mojaveite is trigonal, space group R3, with the unit-cell parameters: a = 8.316(2), c = 13.202(6) Å and V = 790.7(1) Å 3. The eight strongest lines in the powder XRD pattern are [dobs/Å (I) (hkl)]: 4.403(91)(003), 2.672(28)(211), 2.512(100)(212̄ ), 2.110(27)(033,214), 1.889(34)(312,215̄ ,223̄ ), 1.570(39)(404,140,217), 1.481(34)(045,143̄ ,324) and 1.338(14)(422). Diffraction data could not be refined, but stoichiometries and unit-cell parameters imply that bluebellite and mojaveite are very similar in crystal structure. Structure models that satisfy bondvalence requirements are presented that are based on stackings of brucite-like Cu6MX14layers, where M = (I or Te) and X = (O, OH and Cl). Bluebellite and mojaveite provide a rare instance of isotypy between an iodate containing I5+with a stereoactive lone electron pair and a tellurate containing Te6+with no lone pair.

Calciodelrioite, Ca(VO3)2(H2O)4, the Ca analogue of delrioite, Sr(VO3)2(H2O)4

2012 ◽  
Vol 76 (7) ◽  
pp. 2803-2817 ◽  
Author(s):  
A. R. Kampf ◽  
J. Marty ◽  
B. P. Nash ◽  
J. Plášil ◽  
A. V. Kasatkin ◽  
...  
Keyword(s):  
New Mineral ◽  
Unit Cell Parameters ◽  
The West ◽  
Calculated Density ◽  
X Ray ◽  
Cell Parameters ◽  
The Usa ◽  
Perfect Cleavage ◽  
Mohs Hardness ◽  
A Chain

AbstractCalciodelrioite, ideally Ca(VO3)2(H2O)4, is a new mineral (IMA 2012-031) from the uraniumvanadium deposits of the eastern Colorado Plateau in the USA. The type locality is the West Sunday mine, Slick Rock district, San Miguel County, Colorado. The new mineral occurs on fracture surfaces in corvusite- and montroseite-impregnated sandstone and forms as a result of the oxidative alteration of these phases. At the West Sunday mine, calciodelrioite is associated with celestine, gypsum, huemulite, metarossite, pascoite and rossite. The mineral occurs as transparent colourless needles, bundles of tan to brown needles and star bursts of nearly black broad blades composed of tightly intergrown needles. Crystals are elongate and striated parallel to [100], exhibiting the prismatic forms {001} and {011} and having terminations possibly composed of the forms {100} and {611̄}. The mineral is transparent and has a white streak, subadamantine lustre, Mohs hardness of about 2½, brittle tenacity, irregular to splintery fracture, one perfect cleavage on {001} and possibly one or more additional cleavages parallel to [100]. Calciodelrioite is soluble in water. The calculated density is 2.451 g cm– 3. It is optically biaxial (+) with α = 1.733(3), β = 1.775(3), γ = 1.825(3) (white light), 2Vmeas = 87.3(9)° and 2Vcalc = 87°. The optical orientation is X = b; Z ≈ a. No pleochroism was observed. Electronmicroprobe analyses of two calciodelrioite samples and type delrioite provided the empirical formulae (Ca0.88Sr0.07Na0.04K0.01)Σ1.00(V1.00O3)2(H2.01O)4, (Ca0.76Sr0.21Na0.01)Σ0.98(V1.00O3)2(H2.01O)4 and (Sr0.67Ca0.32)Σ0.99(V1.00O3)2(H2.00O)4, respectively. Calciodelrioite is monoclinic, I2/a, with unit-cell parameters a = 14.6389(10), b = 6.9591(4), c = 17.052(2) Å, β = 102.568(9)°, V = 1695.5(3) Å3 and Z = 8. The seven strongest lines in the X-ray powder diffraction pattern [listed as dobs Å (I)(hkl)] are as follows: 6.450(100)(011); 4.350(16)(013); 3.489(18)(020); 3.215(17)(022); 3.027(50)(multiple); 2.560(28)(4̄15,413); 1.786(18)(028). In the structure of calciodelrioite (refined to R1 = 3.14% for 1216 Fo > 4σF), V5+O5 polyhedra link by sharing edges to form a zigzag divanadate [VO3] chain along a, similar to that in the structure of rossite. The chains are linked via bonds to Ca atoms, which also bond to H2O groups, yielding CaO3(H2O)6 polyhedra. The Ca polyhedra form a chain along b. Each of the two symmetrically independent VO5 polyhedra has two short vanadyl bonds and three long equatorial bonds. Calciodelrioite and delrioite are isostructural and are the endmembers of the series Ca(VO3)2(H2O)4–Sr(VO3)2(H2O)4. Calciodelrioite is dimorphous with rossite, which has a similar structure; however, the smaller 8-coordinate Ca site in rossite does not accommodate Sr.

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