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

Abstract

Juabite, 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.

Polytypism in mcalpineite: a study of natural and synthetic Cu3TeO6

“…This phase was first reported from two cotype localities: the McAlpine mine, California, USA (37 45 0 58 00 N, 120 15 0 9 00 W) and the Centennial Eureka mine, Utah, USA (39 56 0 36 00 N, 112 7 0 19 00 ). The latter mine is the type locality for six other Cu-containing Te oxysalt minerals: eurekadumpite [(Cu,Zn) 16 (Te IV O 3 ) 2 -(AsO 4 ) 3 Cl(OH) 18 Á7H 2 O; Pekov et al (2011)], frankhawthorneite [Cu 2 Te VI O 4 (OH) 2 ; Roberts et al (1995)], jensenite [Cu 3 Te 6+ O 6 Á2H 2 O; Roberts et al (1996a)], juabite [CaCu 10 (Te IV O 3 ) 4 (AsO 4 ) 4 (OH) 2 Á4H 2 O; Roberts, Gault et al (1997)], leisingite [Cu 2 MgTe VI O 6 Á6H 2 O; Roberts et al (1996b)] and utahite [MgCu 4 Zn 2 Te VI 3 O 14 (OH) 4 Á6H 2 O; Roberts, Stirling et al (1997b)]. The specimen from the Centennial Eureka Mine was used for H 2 O determination by Roberts et al (1994).…”

Elucidating the natural–synthetic mismatch of Pb2+Te4+O3: The redefinition of fairbankite to Pb122+(Te4+O3)11(SO4)

“…Fairbankite is not a fourth polymorph of Pb (Roberts et al 1997;Kampf and Mills, 2011) and rodalquilarite (Kampf and Mills, 2011) have neso units as part of a larger structural layer, This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America. The published version is subject to change.…”

The crystal-structure determination and redefinition of eztlite, Pb22+Fe33+(Te4+O3)3(SO4)O2Cl

“…Eztlite contains isolated neso tellurite (Te 4+ O 3 ) 2– groups that are part of a larger structural group (a layer based on edge and corner linking of Fe 3+ O 6 octahedra, with tellurite decoration, in this case). The minerals juabite (Roberts et al , 1997; Kampf and Mills, 2011) and rodalquilarite (Feger et al , 1999; Kampf and Mills, 2011) are also in this category, but display no structural similarities to eztlite (Christy et al , 2016). Although also containing Te 4+ , sulfate and chloride in a layered structure, nabokoite is markedly different to eztlite.…”