Pokhodyashinite, CuTlSb 2 (Sb 1- x Tl x )AsS 7- x , a new thallium sulfosalt from the Vorontsovskoe gold deposit, Northern Urals, Russia

Journal of Geosciences

article

Anatoly V. Kasatkin¹  Jakub Plasil²  Emil Makovicky³  Radek Skoda⁴  Atali A. Agakhanov¹  Mikhail V. Tsyganko⁵ 

[1] Fersman Mineralogical Museum of Russian Academy of Sciences;Institute of Physics, Academy of Sciences of the Czech Republic v.v.i;Department of Geoscience and Resource Management, University of Copenhagen;Department of Geological Sciences, Faculty of Science, Masaryk University;ul. 40 let Oktyabra 15

关键词: pokhodyashinite;    new mineral;    copper;    thallium;    sulfosalt;    crystal structure;    Vorontsovskoe gold deposit;    Northern Urals;   

DOI  :  10.3190/jgeosci.342

学科分类：自动化工程

来源: Ceska Geologicka Spolecnost / Czech Geological Society

【 摘 要 】

Pokhodyashinite CuTlSb2(Sb1–xTlx)AsS7–x, is a new sulfosalt from the Vorontsovskoe gold deposit, Sverdlovsk Oblast’,Northern Urals, Russia. It forms anhedral grains up to 0.1×0.05 mm in size in calcite and is associated with major orpiment, pyrite, realgar and minor baryte, clinochlore, As-bearing fluorapatite, harmotome, prehnite, native gold and a richspectrum of sulfosalts. Pokhodyashinite is black, opaque, and has a metallic luster and a black streak. It is brittle, withan uneven fracture and poor cleavage on {100}. The Vickers hardness (VHN, 20 g load) is 55 kg/mm2, correspondingto a Mohs hardness of 2. The calculated density is 5.169 g/cm3. In reflected light, pokhodyashinite is grayish-white,bireflectance is distinct. In crossed polars, it is strongly anisotropic; rotation tints vary from dark brownish gray to lightbluish-gray. No internal reflections are observed. The reflectance values for wavelengths recommended by the Commissionon Ore Mineralogy of the IMA are (Rmin/Rmax, %): 28.9/34.6 (470 nm), 27.6/33.4 (546 nm), 26.7/32.4 (589 nm), 26.1/31.1(650 nm). The empirical formula of pokhodyashinite based on ΣMe = 6 apfu is Cu0.700Ag0.340Tl1.320Pb0.020Sb2.630As0.990S6.625.Pokhodyashinite is monoclinic, space group C2/m, a = 23.431(5), b = 3.996(2), c = 14.070(3) Å, β = 110.23(3)°,V = 1236.1(8) Å3 and Z = 4. Its structure can be described as wavy slabs of a complex structure based on double-rodsof Sb-coordination pyramids and lone-electron-pair interspaces/micelles, separated by wavy interlayers consisting ofpaired columns of Tl and rods of paired Cu-coordination polyhedra. A small amount of Tl-for-Sb substitution results inpartial anion vacancies in one sulfur site. The new mineral is named in honor of Maxim Mikhailovitch Pokhodyashin,a pioneer of mining engineering and smelting works in the Northern Urals of the 18th century.

【 授权许可】

CC BY