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Biagioni, C., Moelo, Y., Merlino, S., Pasero, M., Paar, W. H., Vezzoni, S. & Zaccarini, F. (2019) Arsenmarcobaldiite, Pb-12(As3.2SbS2.8)Sigma=S-6(21), a new N=3.5 jordanite homologue from the Sant'Anna tectonic window, Apuan Alps (Tuscany, Italy). Eur. J. Mineral. 31 1067–1077.
Added by: Richard Baschera (2020-01-20 08:48:56) Last edited by: Richard Baschera (2020-01-20 08:51:32) |
| Type de référence: Article DOI: 10.1127/ejm/2019/0031-2888 Numéro d'identification (ISBN etc.): 0935-1221 Clé BibTeX: Biagioni2019a Voir tous les détails bibliographiques  |
Catégories: IMN, INTERNATIONAL Mots-clés: antimony, Apuan Alps, arsenic, arsenmarcobaldiite, crystal structure, ima commission, jordanite homologous series, kirkiite, lead, new mineral species, sulfosalt, sulfosalts Créateurs: Biagioni, Merlino, Moelo, Paar, Pasero, Vezzoni, Zaccarini Collection: Eur. J. Mineral. |
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| Résumé |
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{The new mineral species arsenmarcobaldiite, Pb-12(As3.2Sb2.8)(Sigma=6)S-21, occurs as black anhedral grains, up to 0.5 mm in size, with metallic lustre, associated with pyrite and minor sphalerite, within layers of granoblastic quartz and accessory baryte embedded in pyrite-rich schist from a small baryte + pyrite prospect at Verzalla, Stazzema, Apuan Alps, Tuscany, Italy. Under the ore microscope, arsenmarcobaldiite is white. It is weakly pleochroic in shades of grey. Anisotropy is distinct, both in air and oil, with rotation tints from brownish to bluish-grey. Reflectance percentages for the four COM wavelengths are [R-min, R-max (%), (lambda)]: 32.8, 38.3 (470 nm); 32.2, 37.5 (546 nm); 31.7, 36.9 (589 nm); 31.4, 36.6 (650 nm). Polysynthetic twinning is common and characteristic. Electron microprobe analysis gave (in wt% - average of 19 spot analyses): Ag 0.20(1), Pb 66.34(38), As 6.36(10), Sb 8.93(9), Bi 0.30(5), S 18.00(14), total 100.13(48). On the basis of Sigma Me = 18 atoms per formula unit, the chemical formula is Ag0.07(1)Pb11.96(5)(As3.17(4)Sb2.74(3)Bi0.05(1))(Sigma 5.96)S-20.970(17), ideally Pb-12(As3.2Sb2.8)(Sigma=6)S-21. The main diffraction lines, corresponding to multiple hkl indices, are [d in angstrom (relative visual intensity)]: 3.595 (m), 3.429 (m), 3.214 (ms), 3.027 (ms), 2.233 (s), 2.125 (ms), 1.839 (ms). The X-ray diffraction study gave a triclinic unit cell, space group P (1) over bar with a = 8.9736(9)
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