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Salt Lake City, UT, United States

Kampf A.R.,Natural History Museum of Los Angeles County | Marty J.,5199 E. Silver Oak Road | Nash B.P.,University of Utah | Plasil J.,ASCR Institute of Physics Prague | And 2 more authors.
Mineralogical Magazine | Year: 2012

Calciodelrioite, ideally Ca(VO3)2(H 2O)4, is a new mineral (IMA 2012-031) from the uranium-vanadium 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 {611}. The mineral is transparent and has a white streak, subadamantine lustre, Mohs hardness of about 2/4, 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. Electron-microprobe analyses of two calciodelrioite samples and type delrioite provided the empirical formulae (Ca0.88Sr 0.07Na0.04K0.01)Σ1.00(V 1.0003)2(H2.01O)4, (Ca 0.76Sr0.21Na0.01)Σ0.98(V 1.00O3)2(H2.01O)4 and (Sr0.67Ca0.32) Σ0.99(V1.00O3)2(H 2.00O)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)(415,413); 1.786(18)(028). In the structure of calciodelrioite (refined to R1 = 3.14% for 1216 Fo > 4σF), V 5+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 H 2O 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. © 2012 The Mineralogical Society. Source


Mills S.J.,Khan Research Laboratories | Kampf A.R.,Natural History Museum of Los Angeles County | Christy A.G.,Australian National University | Housley R.M.,California Institute of Technology | And 2 more authors.
Mineralogical Magazine | Year: 2014

Bluebellite, 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 bluish-green plates or flakes up to ∼20 μm × 20 mm × 5 μm 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)9.80Cl1.09 based 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) å3 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)(212¯), 2.213(9)(006), 2.103(29)(033,214), 1.899(47)(312,215¯), 1.566(48)(140,217) and 1.479(29)(045,143¯,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) å3. 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)(212¯), 2.110(27)(033,214), 1.889(34)(312,215¯,223¯), 1.570(39)(404,140,217), 1.481(34)(045,143¯,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 bond-valence requirements are presented that are based on stackings of brucite-like Cu6MX14 layers, 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. © 2014 The Mineralogical Society. Source


Kampf A.R.,Natural History Museum of Los Angeles County | Mills S.J.,Khan Research Laboratories | Housley R.M.,California Institute of Technology | Marty J.,5199 E. Silver Oak Road
American Mineralogist | Year: 2013

Fuettererite, Pb3Cu2+ 6Te 6+O6(OH)7Cl5, is a new tellurate from Otto Mountain near Baker, California, named for Otto Fuetterer who is largely responsible for the development of the mining claims on Otto Mountain. The new mineral is known from only two specimens, one from the NE2 vein and the other from the Bird Nest drift. Fuettererite occurs in vugs in quartz, on the first specimen associated with Br-rich chlorargyrite, iodargyrite, and telluroperite and on the second specimen associated with anglesite, anatacamite, atacamite, chalcopyrite, galena, goethite, hematite, muscovite, phosphohedyphane, timroseite, and wulfenite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Fuettererite is hexagonal, with space group R3, a = 8.4035(12), c = 44.681(4) Å, V = 2732.6(6) Å3, and Z = 6. Crystals are tabular to short prismatic, exhibit the forms {100}, {101}, and {001} and reach a maximum dimension of 50 μm. The color is bluish green, the streak is pale bluish-green, and the luster is adamantine. The Mohs hardness is estimated at between 2 and 3. The new mineral is brittle with irregular fracture and one perfect cleavage on {001}. The calculated density based on the empirical formula is 5.528 g/cm3. Fuettererite is uniaxial (-), with calculated indices of refraction of ω = 2.04 and ε = 1.97, and is dichroic bluish-green, E < O. Electron microprobe analysis provided: PbO 41.45, CuO 30.35, Al2O3 0.23, TeO3 12.80, Cl 12.08, H2O 3.55 (structure), O=Cl -2.73, total 97.73 wt%. The empirical formula (Equavation Presented) The ten strongest powder X-ray diffraction lines are [dobs in Å (hkl) I]: 6.106 (104) 44, 3.733 (0.0.12) 100, 2.749 (121) 53, 2.6686 (124) 49, 2.5289 (127) 41, 2.2772 (1.2.11) 38, 1.9637 (315, 1.2.16) 87, 1.8999 (multiple) 48, 1.5976 (multiple) 40, and 1.5843 (410, 1.2.23, 143) 44. The crystal structure of fuettererite (R1 = 0.031 for 971 reflections with Fo > 4σF) contains edge-sharing sheets of CuO 5Cl and TeO6 octahedra. These sheets are virtually identical to that in the structure of spangolite, but in fuettererite they are linked together to form a double sheet. The double octahedral sheets alternate with thick double layers of PbO2Cl6 polyhedra. The CuO5Cl octahedra exhibit pronounced Jahn-Teller distortions and the PbO2Cl6 polyhedron has a lopsided distribution of bond lengths attributable to the localization of the Pb2+ 6s2 lone-pair electrons. Source


Kampf A.R.,Natural History Museum of Los Angeles County | Mills S.J.,Khan Research Laboratories | Housley R.M.,California Institute of Technology | Rossman G.R.,California Institute of Technology | And 2 more authors.
American Mineralogist | Year: 2013

Eckhardite, (Ca,Pb)Cu2+Te6+O5(H 2O), is a new tellurate mineral from Otto Mountain near Baker, California, USA. It occurs in vugs in quartz in association with Br-rich chlorargyrite, gold, housleyite, khinite, markcooperite, and ottoite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Eckhardite is monoclinic, space group P21/n, with unit-cell dimensions a = 8.1606(8), b = 5.3076(6), c = 11.4412(15) Å, β = 101.549(7)°, V = 485.52(10) Å3, and Z = 4. It forms as needles or blades up to about 150 × 15 × 5 μm in size, typically in radial or sub-radial aggregates, but also as isolated needles. The color is light bluish green and the streak is very pale bluish green. Crystals are transparent with vitreous to subadamantine luster. The Mohs hardness is estimated at between 2 and 3. Eckhardite is brittle with an irregular fracture and one likely (but not observed) cleavage on {101}. The calculated density based on the empirical formula is 4.644 g/cm3. The mineral is biaxial (-), with indices of refraction of α = 1. 770 (calc), β = 1.860 (calc), and γ = 1.895(5). The measured 2V is 61.2(5)°, dispersion is r < v, perceptible and the optical orientation is Z = b; X ≈ [101]. The pleochroism is: Z (light blue green) < Y (very pale blue green) < X (colorless). The normalized electron microprobe analyses (average of 4) provided: PbO 4.79, CaO 15.90, MgO 0.06, CuO 22.74, Fe2O3 0.06, TeO3 51.01, H 2O 5.45 (structure), total 100 wt%. The empirical formula (based on 6 O apfu) is: Ca0.962Pb0.073Cu0.971 2+Mg0.005Fe0.002 3+Te 0.986 6+ O6H2.052. The Raman spectrum exhibits prominent features consistent with the mineral being a tellurate, as well as an OH stretching feature confirming a hydrous component. The eight strongest powder X ray diffraction lines are [dobs in Å (hkl) I]: 5.94 (101) 100, 3.287 (112) 80, 2.645 (020,2̄13) 89, 2.485 (1̄14,301,014) 48, 2.245 (114,122) 46, 1.809 (223,413,321,4̄04) 40, 1.522 (413,5̄12,421,133) 42, and 1.53 (2̄17,2̄33,4̄06) 43. The crystal structure of eckhardite (R1 = 0.046 for 586 reflections with Fo > 4σF) consists of stair-step-like octahedral layers of Te6+O6 and Cu2+O6 octahedra parallel to {101}, which are linked in the [101̄] direction by bonds to interlayer Ca atoms. The structure can be described as a stacking of stepped HCP layers alternating with chains of CaO7 polyhedra. The structures of bairdite, timroseite, and paratimroseite also contain stair-step-like HCP polyhedral layers. Source


Kampf A.R.,Natural History Museum of Los Angeles County | Mills S.J.,Khan Research Laboratories | Housley R.M.,California Institute of Technology | Rossman G.R.,California Institute of Technology | And 2 more authors.
American Mineralogist | Year: 2013

Bairdite, Pb2Cu4 2+Te2 6+O10(OH)2(SO4)(H2O), is a new tellurate-sulfate from Otto Mountain near Baker, California, U.S.A. It occurs in vugs in quartz associated with khinite, cerussite, goethite, and hematite. It is interpreted as having formed from the partial oxidation of primary sulfides and tellurides during or following brecciation of quartz veins. Bairdite is monoclinic, space group P21/c, with unit-cell dimensions a = 14.3126(10), b = 5.2267(3), c = 9.4878(5) Å, b = 106.815(7)°, V = 679.41(7) Å3, and Z = 2. Bairdite occurs as diamond-shaped tabular crystals up to about 250 mm long and 5 mm thick, in subparallel and fan-shaped aggregates. The color is lime green, the streak is pale lime green, and the luster is adamantine. The Mohs hardness is estimated at between 2 and 3. Bairdite is brittle with an irregular fracture and one perfect cleavage on {100}. The calculated density based on the empirical formula is 6.062 g/cm 3. Bairdite is biaxial (+), with calculated indices of refraction of a = 1.953, b = 1.966, and g = 2.039. The measured 2V is 47(2)°, dispersion is r < v, strong and the optical orientation is Y = b; Z a = 34° in obtuse angle b. The pleochroism is strong: Z (pale green) < < < X (green) < Y (green). Electron microprobe analyses (average of 4) provided: PbO 34.22, CaO 0.06, CuO 23.80, TeO3 26.34, SO3 5.74, H2O 2.81 (structure), total 92.97 wt%. The empirical formula (based on 17 O atoms pfu) is: Pb2.05Ca0.01Cu3.99 2+Te2.00 6+S0.96O 17.00H4.16. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) I]: 4.77 (110,102) 50, 4.522 (002,011,111) 66, 3.48 (multiple) 62, 2.999 (311,411) 97, 2.701 (502,113,213) 79, 2.614 (013,020) 100, 1.727 (multiple) 65, and 1.509 (911,033,324) 83. The crystal structure of bairdite (R1 = 0.072 for 1406 reflections with Fo > 4δF) contains edge-sharing chains of Te 6+O6 and Cu2+O6 octahedra parallel to b that are joined by corner-sharing in the a direction, forming thick stair-step-like hexagonal close packed layers parallel to {100}. The polyhedral sheet has similarities to those in the structures of timroseite and paratimroseite. The thick interlayer region contains PbO10 polyhedra and half-occupied SO4 groups. Raman and infrared spectral data are presented. Source

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