Biagioniite, Tl 2 SbS 2 , from the Hemlo gold deposit, Marathon, Ontario, Canada: occurrence and crystal structure
| Autor: | Yves Moëlo, Luca Bindi |
|---|---|
| Přispěvatelé: | Dipartimento di Scienze della Terra [Firenze] (DST), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Institut des Matériaux Jean Rouxel (IMN), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
010504 meteorology & atmospheric sciences chemistry.chemical_element Crystal structure Electron microprobe engineering.material 010502 geochemistry & geophysics 01 natural sciences Aurostibite Crystallography chemistry.chemical_compound Stibarsen chemistry Antimony Geochemistry and Petrology engineering [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] Pleochroism Isostructural ComputingMilieux_MISCELLANEOUS 0105 earth and related environmental sciences Monoclinic crystal system |
| Zdroj: | Mineralogical Magazine Mineralogical Magazine, Mineralogical Society, 2020, 84 (3), pp.390-397. ⟨10.1180/mgm.2020.27⟩ |
| ISSN: | 0026-461X 1471-8022 |
| DOI: | 10.1180/mgm.2020.27⟩ |
| Popis: | Biagioniite, ideally Tl2SbS2, is a new mineral from the Hemlo gold deposit, Marathon, Ontario, Canada. It occurs as very rare anhedral crystals up to 65 μm across associated with aurostibite, stibarsen and native gold in a calcite matrix. Biagioniite is opaque with a metallic lustre and shows a black streak. In reflected light biagioniite is moderately bireflectant and not pleochroic. Under crossed polars it is weakly anisotropic with blueish to light-blue rotation tints. Internal reflections are absent.Reflectance percentages for the four standard wavelengths (RminandRmax) are 35.9 and 37.5 (471.1 nm); 34.7 and 36.2 (548.3 nm); 33.8 and 35.3 (586.6 nm); and 31.5 and 33.7 (652.3 nm), respectively. A mean of four electron microprobe analyses gave: Tl 65.12(31), Ag 3.52(9), Sb 20.22(12), S 10.80(8), total 99.66 wt.%, corresponding, on the basis of a total of 5 atoms, to (Tl1.87Ag0.19)Σ2.06Sb0.97S1.97. Biagioniite is monoclinic, space groupPc, witha= 11.0895(9),b= 14.3124(11),c= 7.9352(6) Å, β = 96.230(8)°,V= 1252.02(17) Å3andZ= 8. The four strongest powder-diffraction lines [din Å (I/I0) (hkl)] are: 3.56 (100) (310); 3.37 (75) ($\bar{2}$31); 3.79 (60) (012); 3.03 (60) (032). In the crystal structure [R1= 0.024 for 2655 reflections withI> 2σ(I)], thallium adopts various coordinations extending from quasi-linear to quasi-tetrahedral. Antimony forms Sb–Sb pairs, which lead to the formula [Tl+1]4[Sb2]4+[S2–]4. Biagioniite is isostructural with dervillite, Ag2AsS2. The new mineral has been approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2019–120) and named for Cristian Biagioni, Associate Professor of Mineralogy at the Department of Earth Sciences of the University of Pisa, Italy. |
| Databáze: | OpenAIRE |
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