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Biagioni, C., Moelo, Y., Orlandi, P. & Stanley, C. J. (2016) Lead-antimony sulfosalts from Tuscany (Italy). XVII. Meerschautite, (Ag,Cu)(5.5)Pb-42.4(Sb,As)(45.1)S112O0.8, a new expanded derivative of owyheeite from the Pollone mine, Valdicastello Carducci: occurrence and crystal structure. Mineral. Mag. 80 675–690.
Added by: Richard Baschera (2016-09-01 12:37:03) Last edited by: Richard Baschera (2016-09-01 12:46:30) |
| Type de référence: Article DOI: 10.1180/minmag.2016.080.011 Numéro d'identification (ISBN etc.): 0026-461X Clé BibTeX: Biagioni2016a Voir tous les détails bibliographiques  |
Catégories: IMN, INTERNATIONAL Mots-clés: ag, antimony, Apuan Alps, arsenic, as)(22)(as-as)s-56, bond-valence parameters, crystal structure, cu(ag, cu)(3)pb-19(sb, della-vena mine, Italy, lead, meerschautite, new mineral species, oxy-chloro-sulfosalt, Oxygen, parasterryite, pb9sb10s23clo0.5, Pollone mine, silver, sulfosalt, tuscany, x-ray-diffraction, zinkenite group Créateurs: Biagioni, Moelo, Orlandi, Stanley Collection: Mineral. Mag. |
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| Résumé |
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{The new mineral species meerschautite, ideally (Ag,Cu)(5.5)Pb-42.4(Sb, As)(45.1)S112O0.8, has been discovered in the baryte + pyrite +/- (Pb-Zn-Ag) deposit of the Pollone mine, near Valdicastello Carducci, Apuan Alps, Tuscany, Italy. It occurs as black prismatic crystals, striated along [100], up to 2 mm long and 0.5 mm thick, associated with baryte, boulangerite, pyrite, quartz and sphalerite. Meerschautite is opaque with a metallic lustre and shows a black streak. In reflected light, meerschautite is white in colour, weakly bireflectant and non pleochroic. With crossed polars, it is distinctly anisotropic with grey to dark grey rotation tints with brownish and greenish shades. Reflectance percentages for COM wavelengths [lambda (nm), R-air (%)] are: 470: 39.7/41.4; 546: 38.3/39.9; 589: 37.4/39.0; 650: 35.8/37.2. Electron-microprobe data collected on two different samples gave (wt.%): Cu 0.22, Ag 3.15, Tl 0.07, Pb 48.54, Sb 25.41, As 2.82, S 19.74, Se 0.14, Cl 0.03, sum 100.12 (# 1) and Cu 0.22, Ag 3.04, Tl 0.13, Pb 48.53, Sb 25.40, As 2.93, Bi 0.06, S 19.82, Se 0.13, Cl 0.05, sum 100.31 (# 2). On the basis of 112 anions (S+Se+Cl) per formula unit, the empirical formulae are (Ag(5.29)Cu(0.6)3)(Sigma 5.92)(Pb42.43Tl0.06)(Sigma 42.49)(Sb37.80As6.82)(Sigma 44.62)(S111.53Se0.32Cl0.15)(Sigma 112) (# 1) and (Ag5.08Cu0.62)(Sigma 5.70) (Pb42.22Tl0.12)(Sigma 42.34)(Sb37.61As7.07Bi0.05)(Sigma 44.73)(S111.45Se0.30Cl0.25)(Sigma 112) (# 2). Main diffraction lines, corresponding to multiple hkl indices, are [d in angstrom (relative visual intensity)]: 3.762 (m), 3.663 (s), 3.334 (vs), 3.244 (s), 3.016 (m), 2.968 (m), 2.902 (m), 2.072 (ms). The crystal structure study gave a monoclinic unit cell, space group P2(1), with a = 8.2393(1)
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