Agardite-(Nd) NdCu6(AsO4)3(OH)6·3H2O from the Hilarion Mine, Lavrion, Greece: mineral description and chemical relations with other members of the agardite-zálesíite solid-solution system

Pekov, Igor V.; Чуканов, Н. В.; Zadov, Aleksandr E.; Voudouris, Panagiotis; Magganas, Andreas; Katerinopoulos, A.

doi:10.3190/jgeosci.099

Cited by 3 publications

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References 8 publications

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“…The empirical formula of the mixite-group mineral has been calculated on the basis of O = 12 and OH = 6, Σcation = 10, or P + As + Si = 3 (e.g., Olmi et al, 1991;Miyawaki et al, 2000;Walenta and Theye, 2005;Pekov et al, 2011;Morrison et al, 2016). The formula based on O = 12 and OH = 6 is, on the other hand, unstable for Caand Si-bearing systems which involve hydrogen.…”

Section: Chemical Compositionmentioning

confidence: 99%

Petersite–(La), a new mixite–group mineral from Ohgurusu, Kiwa, Kumano City, Mie Prefecture, Japan

Nishio–Hamane

Ohnishi²,

Shimobayashi

et al. 2020

Journal of Mineralogical and Petrological Sciences

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Petersite-(La) is a new mineral of the petersite series in the mixite group with an ideal formula of Cu 6 La (PO 4) 3 (OH) 6 •3H 2 O from Ohgurusu, Kiwa-cho, Kumano City, Mie Prefecture, Japan. The mixite-group minerals occur in small cavities coated by chrysocolla developed along quartz veins. Four members from different cavities have been identified: petersite-(La), petersite-(Ce), petersite-(Y), and agardite-(La). Petersite-(La) occurs as a radial aggregate formed by acicular to hexagonal columnar crystals of yellowish green color. Crystals are elongated along [001] and the prismatic face is probably formed by {001} and {100} or {110}. It is nonfluorescent in UV light. Crystals are brittle, cleavage and parting are non-observed, and fracture is uneven. These characteristics are common in other mixite-group minerals. The calculated density of petersite-(La) is 3.33 g/cm 3 , based on the empirical formula and powder XRD data. It is optically uniaxial positive with ω = 1.680(3) and ε = 1.767(3) (white light), and pleochroism varies from light green to yellowish green. Based on the WDS analysis, the empirical formula of petersite-(La) calculated on the basis of P + As + Si = 3 is (Cu 5.692 Fe 0.010) Σ5.702 [(La 0.148 Ce 0.122 Nd 0.117 Y 0.086 Sm 0.022) Σ0.495 Ca 0.372 ] Σ0.866 (P 1.890 As 0.799 Si 0.311) Σ3 O 10.320 (OH) 7.680 •3H 2 O. Petersite-(La) is hexagonal (P6 3 /m) with a = 13.367(2) Å, c = 5.872(2) Å, and V = 908.7(4) Å 3 (Z = 2). The eight strongest lines of petersite-(La) in the powder XRD pattern [d in Å(I/I 0)(hkl)] are 11.

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Section: Chemical Compositionmentioning

confidence: 99%

Petersite–(La), a new mixite–group mineral from Ohgurusu, Kiwa, Kumano City, Mie Prefecture, Japan

Nishio–Hamane

Ohnishi²,

Shimobayashi

et al. 2020

Journal of Mineralogical and Petrological Sciences

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Petersite-(Ce), Cu²⁺₆Ce(PO₄)₃(OH)₆·3H₂O, A New Mixite Group Mineral From Yavapai County, Arizona, USA

et al. 2016

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A new mineral, petersite-(Ce), ideally Cu 2þ 6 Ce(PO 4) 3 (OH) 6 Á3H 2 O (IMA2014-002), has been found in the Cherry Creek District of Yavapai County, Arizona, USA. It is a secondary alteration mineral associated with malachite, chlorite, a biotite phase, quartz, albite, orthoclase, hematite, chalcopyrite, and an uncharacterized hisingerite-like mineral. Petersite-(Ce) occurs as sprays of yellowish-green, acicular crystals approximately 20 3 20 3 50 lm in size. It has a white streak with vitreous luster. The mineral is brittle and has a Mohs hardness of~3.5; no cleavage or parting was observed. The calculated density is 3.424 g/ cm 3. An electron microprobe analysis resulted in an empirical chemical formula of Cu 6.05 (Ce 0.18 Y 0.16 La 0.12 Nd 0.09 Gd 0.03 Pr 0.02 Dy 0.01 Sm 0.01 Ca 0.42) R1.04 [(PO 4) 2.54 (SiO 4) 0.14 (PO 3 OH) 0.32 (OH) 6 ]Á3.65H 2 O. Petersite-(Ce) is hexagonal, with space group P6 3 /m and unit-cell parameters a 13.2197(18)Å, c 5.8591(9)Å, and V 886.8(4)Å 3 , Z ¼ 2. It is the Ce analogue of petersite-(Y) and exhibits the mixite structure type. The mixite group can be expressed by the general formula Cu 2þ 6 A(TO 4) 3 (OH) 6 Á3H 2 O, where nine-coordinated A is a rare earth element, Al, Ca, Pb, or Bi, and T is P or As. The structure of petersite-(Ce) is characterized by chains of edge-sharing CuO 5 square-pyramids along c. These chains are connected in the a-b plane by edge-sharing CeO 9 polyhedra and corner-sharing PO 4 tetrahedra. Hydroxyl groups occupy each corner of the CuO 5 polyhedra not shared by a neighboring P or Ce atom. Each CeO 9 polyhedron is surrounded by three zeolitic channels. The walls of the channels, parallel to c, are six-membered, hexagonal rings composed of CuO 5 and PO 4 polyhedra in a ratio of 2:1, respectively, and contain H 2 O molecules. In our model of petersite-(Ce), we defined one distinct H 2 O site positioned to form a ring inside the channel, although there are many statistically possible locations.

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Supergénne minerály z U-Cu rudného výskytu Východná-Nižný Chmelienec v Nízkych Tatrách (hronikum, Slovensko)

Hoppanová¹,

Ferenc²,

Kopáčik³

et al. 2021

Bull Mineral Petrolog

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An association of supergene U-Cu and Y/REE minerals was found in a relic of old ore dump at the abandoned U deposit occurrence Východná-Nižný Chmelienec, the northern slopes of the Nízke Tatry Mts., Slovakia. They have partially recent origin, since exploration of the locality took place between 1965 and 1966. The studied mineral assem- blage is represented by goethite, malachite, uranophane and (meta)zeunerite, in a lesser extent baryte and rare zálesíite. Uranophane appears separately (globular aggregates, thin coatings) and it also forms the main part of the yellow to yellow-green crystalline crusts on the rock cracks. The chemical composition of the uranophane was determined by electron microprobe analyses and it is close to its ideal chemical formula Ca(UO2)2(SiO3OH)2·5H2O. The average chemical composition of the studied uranophane can be expressed by an empirical formula (Ca1.0Mg0.02K0.01Fe0.01Ba0.01)Σ1.05 (UO2)2.08(SiO3OH)1.84·5H2O. The infrared vibrational spectra of the studied uranophane show 3 (UO2)2+ at 850-760 cm-1; the 3 (SiO4)4- antisymmetric stretching vibration at 1000-900 cm-1; the 1 (SiO4)4- symmetric stretching vibration at 1150-1199 cm-1; the  H2O bending vibration at 1800-1600 cm-1 and OH stretching vibrations at 3407; 3408 and 3409 cm-1. The weak bands 2648; 2646 and 2651 cm-1 may be assigned to organic impurities. The calculated U-O bond length 1.83 Å corresponds to short U-O bonds in uranophane. The accessory admixtures of uranophane coatings are (meta)zeunerite and zálesíite. (Meta)zeunerite occasionally forms thin coatings of light green to emerald green tabular crystals (up tu 0.5 mm) on the surface of the rocks. Chemical analyses of (meta)zeunerite correspond to the empirical formula (Cu0.66K0.03Fe0.01Ca0.01)Σ0.71(UO2)2.11[(AsO4)1.96(PO4)0.01]Σ1.97·12H2O. Zálesíite occurs as crystalline aggregates, nests, formed by tiny acicular crystals, up to 100 µm in length. This is the second finding (occurrence) of this mineral in Slovakia. An average zálesíite chemical composition is (Ca0.83REE0.18U0.05Al0.03Ti0.01)Σ1.10(Cu5.81Fe0.06Zn0.02)Σ5.90[(AsO4)2.75 (SiO4)0.21(PO4)0.02(SO4)0.03]Σ3.01(OH)5.10·3H2O. Malachite, which has been also found in the association, is only a minor mineral in the studied locality. The formation of uranyl silicates (uranophane) and minerals of the mixite group (zálesíite), present at the studied locality, points to neutralization of acidic supergene fluids in the mine dumps. Possibly, this environment later (precipitation of baryte) passed to neutral or slightly basic conditions (precipitation of carbonates - malachite). The identified uranyl phosphates/arsenates (zeunerite/metazeunerite), typical of an acidic environment, are therefore rare.

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Agardite-(Nd) NdCu6(AsO4)3(OH)6·3H2O from the Hilarion Mine, Lavrion, Greece: mineral description and chemical relations with other members of the agardite-zálesíite solid-solution system

Cited by 3 publications

References 8 publications

Petersite–(La), a new mixite–group mineral from Ohgurusu, Kiwa, Kumano City, Mie Prefecture, Japan

Petersite–(La), a new mixite–group mineral from Ohgurusu, Kiwa, Kumano City, Mie Prefecture, Japan

Petersite-(Ce), Cu²⁺₆Ce(PO₄)₃(OH)₆·3H₂O, A New Mixite Group Mineral From Yavapai County, Arizona, USA

Supergénne minerály z U-Cu rudného výskytu Východná-Nižný Chmelienec v Nízkych Tatrách (hronikum, Slovensko)

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Agardite-(Nd) NdCu6(AsO4)3(OH)6·3H2O from the Hilarion Mine, Lavrion, Greece: mineral description and chemical relations with other members of the agardite-zálesíite solid-solution system

Cited by 3 publications

References 8 publications

Petersite–(La), a new mixite–group mineral from Ohgurusu, Kiwa, Kumano City, Mie Prefecture, Japan

Petersite–(La), a new mixite–group mineral from Ohgurusu, Kiwa, Kumano City, Mie Prefecture, Japan

Petersite-(Ce), Cu2+6Ce(PO4)3(OH)6·3H2O, A New Mixite Group Mineral From Yavapai County, Arizona, USA

Supergénne minerály z U-Cu rudného výskytu Východná-Nižný Chmelienec v Nízkych Tatrách (hronikum, Slovensko)

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Petersite-(Ce), Cu²⁺₆Ce(PO₄)₃(OH)₆·3H₂O, A New Mixite Group Mineral From Yavapai County, Arizona, USA