Rozhdestvenskayaite Ag10Zn2Sb4S13 and argentotetrahedrite Ag6Cu4(Fe2+,Zn)2Sb4S13: two Ag-dominant members of the tetrahedrite group

Welch, Mark D.; Stanley, Chris J.; Spratt, John; Mills, Stuart J.

doi:10.1127/ejm/2018/0030-2773

Cited by 33 publications

(89 citation statements)

References 10 publications

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“…Freibergite with as much as 46.4 wt.% of Ag (8.93 apfu) was described from the Rejzské pásmo Lode in the Kutná Hora ore district [18]. This phase corresponds to the newly approved mineral rozhdestvenskayaite [63]. Ag and Cu contents show an excellent negative correlation (Figure 17a), which is in agreement with published results (e.g., [35,64,65]).…”

Section: Minerals Of the Tetrahedrite Seriessupporting

confidence: 87%

Ag-Pb-Sb Sulfosalts and Se-rich Mineralization of Anthony of Padua Mine near Poličany—Model Example of the Mineralization of Silver Lodes in the Historic Kutná Hora Ag-Pb Ore District, Czech Republic

2019

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Significant selenium enrichment associated with selenides and previously unknown Ag-Pb-Sb, Ag-Sb and Pb-Sb sulfosalts has been discovered in hydrothermal ore veins in the Anthony of Padua mine near Poličany, Kutná Hora ore district, central Bohemia, Czech Republic. The ore mineralogy and crystal chemistry of more than twenty silver minerals are studied here. Selenium mineralization is evidenced by a) the occurrence of selenium minerals, and b) significantly increased selenium contents in sulfosalts. Identified selenium minerals include aguilarite and selenides naumannite and clausthalite. The previously unknown sulfosalts from Kutná Hora are identified: Ag-excess fizélyite, fizélyite, andorite IV, andorite VI, unnamed Ag-poor Ag-Pb-Sb sulfosalts, semseyite, stephanite, polybasite, unnamed Ag-Cu-S mineral phases and uytenbogaardtite. Among the newly identified sulfides is argyrodite; germanium is a new chemical element in geochemistry of Kutná Hora. Three types of ore were recognized in the vein assemblage: the Pb-rich black ore (i) in quartz; the Ag-rich red ore (ii) in kutnohorite-quartz gangue; and the Ag-rich ore (iii) in milky quartz without sulfides. The general succession scheme runs for the Pb-rich black ore (i) as follows: galena – boulangerite (– jamesonite) – owyheeite – fizélyite – Ag-exces fizélyite – andorite IV – andorite VI – freieslebenite – diaphorite – miargyrite – freibergite. For the Ag-rich red ore (ii) and ore (iii) the most prominent pattern is: galena – diaphorite – freibergite – miargyrite – pyragyrite – stephanite – polybasite – acanthite. The parallel succession scheme progresses from Se-poor to Se-rich phases, i.e., galena – members of galena – clausthalite solid solution – clausthalite; miargyrite – Se-rich miargyrite; acanthite – aguilarite – naumannite. A likely source of selenium is in the serpentinized ultrabasic bodies, known in the area of “silver” lodes in the South of the ore district, which may enable to pre-concentrate selenium, released into hydrothermal fluids during tectonic events. The origin of the studied ore mineralization is primarily bound to the youngest stage of mineralization of the whole ore district, corresponding to the Ag-Sb sequence of the ´eb´ ore type of the Freiberg ore district in Saxony (Germany) and shows mineralogical and geochemical similarities to low-sulfidation epithermal-style Ag-Au mineralization.

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Section: Minerals Of the Tetrahedrite Seriessupporting

confidence: 87%

Ag-Pb-Sb Sulfosalts and Se-rich Mineralization of Anthony of Padua Mine near Poličany—Model Example of the Mineralization of Silver Lodes in the Historic Kutná Hora Ag-Pb Ore District, Czech Republic

2019

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“…It is not unlikely that such a minor amount of vacancy could be overlooked, because the overestimated site scattering (29 electrons vs. 27.1 electrons, as calculated from chemical data) would be partially masked by the relatively large U eq value due to the positional disorder affecting the M (2) site, that is actually split into two flat pyramidal sub-sites, as reported previously by other authors (e.g. Andreasen et al ., 2008; Welch et al ., 2018). The splitting of this position did not improve significantly the crystal structure refinement of tetrahedrite-(Hg) and consequently an unsplit model was preferred.…”

Section: Resultsmentioning

confidence: 99%

Tetrahedrite-(Hg), a new ‘old’ member of the tetrahedrite group

Biagioni

Sejkora

Musetti

et al. 2020

MinMag

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Tetrahedrite-(Hg), Cu6(Cu4Hg2)Sb4S13, has been approved as a new mineral species using samples from Buca della Vena mine (hereafter BdV), Italy, Jedová hora (Jh), Czech Republic and Rožňava (R), Slovakia. It occurs as anhedral grains or as tetrahedral crystals, black in colour, with metallic lustre. At BdV it is associated with cinnabar and chalcostibite in dolomite veins. At Jh, tetrahedrite-(Hg) is associated with baryte and chalcopyrite in quartz–siderite–dolomite veins; at R it is associated with quartz in siderite–quartz veins. Tetrahedrite-(Hg) is isotropic, greyish-white in colour, with creamy tints. Minimum and maximum reflectance data for Commission on Ore Mineralogy wavelengths in air (BdV sample), R in %) are 32.5 at 420 nm; 32.9 at 546 nm; 33.2 at 589 nm; and 30.9 at 650 nm. Chemical formulae of the samples studied, recalculated on the basis of 4 (As + Sb + Bi) atoms per formula unit, are: (Cu9.44Ag0.07)Σ9.51(Hg1.64Zn0.36Fe0.06)Σ2.06Sb4(S12.69Se0.01)Σ12.70 (BdV), Cu9.69(Hg1.75Fe0.25Zn0.06)Σ2.06(Sb3.94As0.06)S12.87 (Jh) and (Cu9.76Ag0.04) Σ9.80(Hg1.83Fe0.15Zn0.10)Σ2.08(Sb3.17As0.58Bi0.25)S13.01 (R). Tetrahedrite-(Hg) is cubic, I $\overline 4 $ 3m, with a = 10.5057(8) Å, V = 1159.5(3) Å3 and Z = 2 (BdV). Unit-cell parameters for the other two samples are a = 10.4939(1) Å and V = 1155.61(5) Å3 (Jh) and a = 10.4725(1) Å and V = 1148.55(6) Å3 (R). The crystal structure of tetrahedrite-(Hg) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.019 on the basis of 335 reflections with Fo > 4σ(Fo) and 20 refined parameters. Tetrahedrite-(Hg) is isotypic with other members of the tetrahedrite group. Mercury is hosted at the tetrahedrally coordinated M(1) site, along with minor Zn and Fe. The occurrence of Hg at this position agrees both with the relatively large M(1)–S(1) bond distance (2.393 Å) and the refined site scattering. Previous occurrences of Hg-rich tetrahedrite and tetrahedrite-(Hg) are reviewed, and its relations with other Hg sulfosalts are discussed.

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“…Vacancies are not very common in minerals of the tetrahedrite group but have been confirmed through structural studies (e.g., Maske and Skinner 1971;Makovicky and Skinner 1979;Rozhdestvenskaya et al 1993;Makovicky et al 2005;Welch et al 2018). The chemical vari ability encompasses anions too, with the substitution of S by Se, or with the occurrence of vacancies (Biagioni et al 2020a).…”

Section: Chemical Compositionmentioning

confidence: 93%

Pošepnýite, a new Hg-rich member of the tetrahedrite group from Příbram, Czech Republic

Škácha¹,

Sejkora²,

Plášil³

et al. 2020

Jour. Geosci.

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The new mineral pošepnýite was found in the mine dump of the shaft No. 16 Háje, one of the mines in the Příbram uranium and base-metal district, central Bohemia, Czech Republic. Pošepnýite is associated with příbramite, dzharkenite, ferroselite, hakite-(Hg), tetrahedrite-(Zn), antimonselite and uraninite in a calcite-dominant gangue. The new mineral occurs as idiomorphic to hypidiomorphic grains up to 100 μm in size. Pošepnýite is steel-grey and has a metallic lustre. Mohs hardness is ca. 3.5-4; the calculated density is 6.23 g cm-3. In reflected light, pošepnýite is light brown. No bireflectance, pleochroism, anisotropy or internal reflections were observed. The average empirical formula, based on electron-microprobe analyses (62 spot analyses), is (Cu 3.33 Ag 0.28) Σ3.61 (Hg 3.43 Cu 2.50 Zn 0.03 Cd 0.03 Fe 0.01) Σ6.00 (Sb 3.88 As 0.12) Σ4.00 (Se 10.83 S 1.29) Σ12.12. The ideal formula is (Cu + 3+x □ 3-x) Σ6 (Hg 2+ 4-x Cu + 2+x) Σ6 Sb 4 (Se 12.5 □ 0.5) Σ13 , 0 ≤ x << 2, which requires Cu 12.25, Hg 30.93, Sb 18.77 and Se 38.05, total 100.00 wt. % (for x = 0) or Cu 17.65, Hg 23.87, Sb 19.32, Se 39.16, total 100.00 wt. % (for x = 1). Pošepnýite is cubic, I-43m, a = 10.964(1) Å, with V = 574.82(15) Å 3 and Z = 2. The strongest reflections of the calculated powder X-ray diffraction pattern are [d, Å (I) (hkl)] are: 3.165(100) (222), 2.930(24) (321), 2.0017(16) (521), 1.9381(65) (440), 1.6528(31) (622)]. According to the single-crystal X-ray diffraction data (R obs = 0.051), pošepnýite is isostructural with minerals of the tetrahedrite group. The cubic structure of pošepnýite is a tetrahedral framework with cavities and a part of tetrahedra replaced by SbSe 3 coordination pyramids. It has one type of pyramidal Sb position, one type of tetrahedrally coordinated cation position M1 occupied by (Hg, Cu), and one type of partly vacant cation site M2 with triangular coordination. The main anion site Se1 participates in all of these cation coordination polyhedra. Minority anion 'Se2' ties the six coordination triangles of Cu2 in the cavity of the tetrahedral framework into one cluster. Pošepnýite is named after the František Pošepný, a famous 19 th-century geologist, often regarded as the father of the modern economic geology.

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Rozhdestvenskayaite Ag10Zn2Sb4S13 and argentotetrahedrite Ag6Cu4(Fe2+,Zn)2Sb4S13: two Ag-dominant members of the tetrahedrite group

Cited by 33 publications

References 10 publications

Ag-Pb-Sb Sulfosalts and Se-rich Mineralization of Anthony of Padua Mine near Poličany—Model Example of the Mineralization of Silver Lodes in the Historic Kutná Hora Ag-Pb Ore District, Czech Republic

Ag-Pb-Sb Sulfosalts and Se-rich Mineralization of Anthony of Padua Mine near Poličany—Model Example of the Mineralization of Silver Lodes in the Historic Kutná Hora Ag-Pb Ore District, Czech Republic

Tetrahedrite-(Hg), a new ‘old’ member of the tetrahedrite group

Pošepnýite, a new Hg-rich member of the tetrahedrite group from Příbram, Czech Republic

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