BIAGIONI, Cristian, Anatoly V. KASATKIN, Fabrizio NESTOLA, Radek ŠKODA, Vladislav V. GURZHIY, Atali A. AGAKHANOV and Natalia N. KOSHLYAKOVA. Zvěstovite-(Fe), Ag6(Ag4Fe2)As4S13, a new member of the tetrahedrite group from the Ulatayskoe Ag–Cu–Co occurrence, eastern Siberia, Russia. European Journal of Mineralogy. Copernicus Publications, 2024, vol. 36, No 3, p. 529-540. ISSN 0935-1221. Available from: https://dx.doi.org/10.5194/ejm-36-529-2024.
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Basic information
Original name Zvěstovite-(Fe), Ag6(Ag4Fe2)As4S13, a new member of the tetrahedrite group from the Ulatayskoe Ag–Cu–Co occurrence, eastern Siberia, Russia
Authors BIAGIONI, Cristian, Anatoly V. KASATKIN, Fabrizio NESTOLA, Radek ŠKODA (203 Czech Republic, belonging to the institution), Vladislav V. GURZHIY, Atali A. AGAKHANOV and Natalia N. KOSHLYAKOVA.
Edition European Journal of Mineralogy, Copernicus Publications, 2024, 0935-1221.
Other information
Original language English
Type of outcome Article in a journal
Field of Study 10504 Mineralogy
Country of publisher Germany
Confidentiality degree is not subject to a state or trade secret
WWW URL
Impact factor Impact factor: 2.100 in 2022
Organization unit Faculty of Science
Doi http://dx.doi.org/10.5194/ejm-36-529-2024
UT WoS 001274007200001
Keywords in English TENNANTITE; REFINEMENT; CELL
Tags rivok
Tags International impact, Reviewed
Changed by Changed by: Mgr. Marie Šípková, DiS., učo 437722. Changed: 7/8/2024 13:34.
Abstract
The new mineral zvěstovite-(Fe), ideally Ag6(Ag4Fe2)As4S13, has been found in the small abandoned Ulatayskoe Ag–Cu–Co occurrence, Ovyurskiy District, Tuva Republic, eastern Siberia, Russia. It occurs as anhedral grains, up to 1 × 0.4 mm in size but usually much smaller, closely intergrown with native silver, in Mg-bearing siderite–quartz gangue. Other associated minerals include acanthite, cobaltite, As-rich members of the tetrahedrite group (kenoargentotennantite-(Fe), tennantite-(Zn), zvěstovite-(Zn)), gersdorffite, jalpaite, krutovite, löllingite, pearceite, safflorite, skutterudite, Br-bearing chlorargyrite, malachite, and muscovite. Zvěstovite-(Fe) is iron black and opaque and has a black streak and metallic lustre. It is brittle and has a conchoidal fracture. No cleavage or parting is observed. The Vickers micro-indentation hardness (Vickers hardness number, VHN; 25 g load) is 169 kg mm−2 (range of 149–187 kg mm−2, n=4), corresponding to a Mohs hardness of 3–3.5. The calculated density is 4.979 g cm−3. In reflected light, zvěstovite-(Fe) is light grey with a greenish tint and isotropic. Internal reflections are ubiquitous and deep red in colour. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are (R, %): 32.5 (470 nm), 31.1 (546 nm), 30.1 (589 nm), and 28.8 (650 nm). The chemical composition (wt %, electron microprobe data, mean of eight spot analyses) is as follows: Cu 1.81, Ag 56.02, Fe 4.60, Zn 0.01, As 13.85, Sb 2.63, S 21.50, total 100.42. The empirical formula, calculated on the basis of 16 atoms per formula unit, is Ag9.93Cu0.54Fe1.58As3.54Sb0.41S12.83. Zvěstovite-(Fe) is cubic and has a space group of 3m, with a=10.8601(3), V=1280.86(11) Å3, and Z=2. The strongest lines of the X-ray powder diffraction pattern (d, Å (I, %) hkl) are 7.68 (11) 110, 3.136 (100) 222, 2.717 (12) 400, 1.984 (8) 521, 1.921 (23) 440, and 1.638 (11) 622. The crystal structure of zvěstovite-(Fe) was refined to R1=0.0551 for 400 unique reflections with Fo>4σ (Fo). The possible ordering of the split M(2) sites is discussed. The new mineral is the Fe isotype of zvěstovite-(Zn). Both these minerals form the zvěstovite series within the tetrahedrite group.
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