Ambrinoite, ideally (K,NH4)(2)(As,Sb)(8)S-13 center dot H2O, occurs as a rare sulfosalt species in the Triassic evaporitic formation of Gessi (gypsum) outcropping near the hamlet of Signols (Oulx, Susa Valley, Torino, Piedmont, Italy). The new species is associated with sulfur and orpiment; in the same occurrence galkhaite, stibnite, and enargite were also identified. Ambrinoite occurs as aggregates of tabular crystals up to 1 mm in length. The color is red, with an orange-red streak; the luster is vitreous to resinous. The mineral is transparent; its microhardness VHN(10 g) = 30 kg/mm(2), corresponding to a Mohs hardness of about 2. Electron microprobe analysis gives the empirical formula [K-1.43(NH4)(0.42)Na0.02Tl0.01](Sigma=1.88) (As5.82Sb2.18)(Sigma=8.00)S-13.22 center dot 1.2H(2)O, close to stoichiometric [K-1.5(NH4)(0.5)](Sigma=2)(As6Sb2)(Sigma=8)S-13 center dot H2O; the calculated density is 3.276 g/cm(3). Micro-Raman spectroscopy confirmed the presence of water and ammonium cation. Ambrinoite is triclinic, space group P (1) over bar, with a = 9.704(1), b = 11.579(1), c = 12.102(2) angstrom, alpha = 112.82(1), beta = 103.44(1), gamma = 90.49(1)degrees, V = 1211.6(3) angstrom(3), Z = 2. The strongest X-ray powder diffraction lines [d in angstrom (I) (hkl)] are: 10.78 (100) (001), 5.79 (55) (0 (2) over bar1), 4.23 (35) (102), 5.31 (34) ((1) over bar 02), 5.39 (32) (002). Its crystal structure has been solved by X-ray single-crystal diffraction on the basis of 2667 unique reflections, with a final R = 0.035. It is formed by two kinds of modules: slabs (110)(pbs) of modified PbS archetype (type A slabs) and openwork slabs with channels accomodating (K,NH4)(+) cations and H2O molecules (type B slabs). Its structure can be described as an order-disorder (OD) structure, built up by two different kinds of layers. Taking into account only the short (As,Sb)-S bonds, (As,Sb)S-3 triangular pyramids form double chains similar to those described in other natural and synthetic compounds, among which its homeotype gillulyite, as well as gerstleyite. Ambrinoite belongs to the hutchinsonite merotypic family. It is probably the product of late-stage hydrothermal fluid circulation. The name of this new mineral species (IMA 2009-071) honors Pierluigi Ambrino (b. 1947), the mineral collector who kindly provided us with the studied specimens.

Ambrinoite, (K,NH4)2(As,Sb)8S13.H2O, a new mineral from Upper Susa Valley, Piedmont, Italy: the first natural (K,NH4)-hydrated sulfosalt / C., Biagioni; E., Bonaccorsi; M., Pasero; Y., Moëlo; M. E., Ciriotti; Bersani, Danilo; A. M., Callegari; M., Boiocchi. - In: AMERICAN MINERALOGIST. - ISSN 0003-004X. - 96:(2011), pp. 878-887. [10.2138/am.2011.3723]

Ambrinoite, (K,NH4)2(As,Sb)8S13.H2O, a new mineral from Upper Susa Valley, Piedmont, Italy: the first natural (K,NH4)-hydrated sulfosalt

BERSANI, Danilo;
2011-01-01

Abstract

Ambrinoite, ideally (K,NH4)(2)(As,Sb)(8)S-13 center dot H2O, occurs as a rare sulfosalt species in the Triassic evaporitic formation of Gessi (gypsum) outcropping near the hamlet of Signols (Oulx, Susa Valley, Torino, Piedmont, Italy). The new species is associated with sulfur and orpiment; in the same occurrence galkhaite, stibnite, and enargite were also identified. Ambrinoite occurs as aggregates of tabular crystals up to 1 mm in length. The color is red, with an orange-red streak; the luster is vitreous to resinous. The mineral is transparent; its microhardness VHN(10 g) = 30 kg/mm(2), corresponding to a Mohs hardness of about 2. Electron microprobe analysis gives the empirical formula [K-1.43(NH4)(0.42)Na0.02Tl0.01](Sigma=1.88) (As5.82Sb2.18)(Sigma=8.00)S-13.22 center dot 1.2H(2)O, close to stoichiometric [K-1.5(NH4)(0.5)](Sigma=2)(As6Sb2)(Sigma=8)S-13 center dot H2O; the calculated density is 3.276 g/cm(3). Micro-Raman spectroscopy confirmed the presence of water and ammonium cation. Ambrinoite is triclinic, space group P (1) over bar, with a = 9.704(1), b = 11.579(1), c = 12.102(2) angstrom, alpha = 112.82(1), beta = 103.44(1), gamma = 90.49(1)degrees, V = 1211.6(3) angstrom(3), Z = 2. The strongest X-ray powder diffraction lines [d in angstrom (I) (hkl)] are: 10.78 (100) (001), 5.79 (55) (0 (2) over bar1), 4.23 (35) (102), 5.31 (34) ((1) over bar 02), 5.39 (32) (002). Its crystal structure has been solved by X-ray single-crystal diffraction on the basis of 2667 unique reflections, with a final R = 0.035. It is formed by two kinds of modules: slabs (110)(pbs) of modified PbS archetype (type A slabs) and openwork slabs with channels accomodating (K,NH4)(+) cations and H2O molecules (type B slabs). Its structure can be described as an order-disorder (OD) structure, built up by two different kinds of layers. Taking into account only the short (As,Sb)-S bonds, (As,Sb)S-3 triangular pyramids form double chains similar to those described in other natural and synthetic compounds, among which its homeotype gillulyite, as well as gerstleyite. Ambrinoite belongs to the hutchinsonite merotypic family. It is probably the product of late-stage hydrothermal fluid circulation. The name of this new mineral species (IMA 2009-071) honors Pierluigi Ambrino (b. 1947), the mineral collector who kindly provided us with the studied specimens.
2011
Ambrinoite, (K,NH4)2(As,Sb)8S13.H2O, a new mineral from Upper Susa Valley, Piedmont, Italy: the first natural (K,NH4)-hydrated sulfosalt / C., Biagioni; E., Bonaccorsi; M., Pasero; Y., Moëlo; M. E., Ciriotti; Bersani, Danilo; A. M., Callegari; M., Boiocchi. - In: AMERICAN MINERALOGIST. - ISSN 0003-004X. - 96:(2011), pp. 878-887. [10.2138/am.2011.3723]
File in questo prodotto:
File Dimensione Formato  
Ambrinoite (K,NH4)2(As,Sb)8S13 a new mineral from upper susa valley.PDF

non disponibili

Tipologia: Documento in Post-print
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 4.62 MB
Formato Adobe PDF
4.62 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Ambrinoite-abstract.pdf

non disponibili

Tipologia: Abstract
Licenza: Creative commons
Dimensione 251.78 kB
Formato Adobe PDF
251.78 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2361676
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 7
social impact