Abstract A new occurrence of kintoreite, ideally PbFe 3 (PO 4 )(PO 3 OH)(OH) 6 , is described from the Tripi mine, Alì, Peloritani Mountains, northeastern Sicily, Italy. Kintoreite occurs as yellow equant crystals, up to 0.05 mm in size, on quartz, associated with another alunite-supergroup mineral currently under study. The studied grains of kintoreite are chemically zoned, showing the occurrence of two distinct domains. Electron microprobe analyses gave (in wt.%): SO 3 5.47(27), P 2 O 5 17.55(14), Al 2 O 3 7.81(35), Fe 2 O 3 23.81(44), PbO 35.11(41), H 2 O calc 9.93, total 99.68 (darker domains) and SO 3 6.03(5), P 2 O 5 16.66(23), Al 2 O 3 4.22(2), Fe 2 O 3 27.31(6), PbO 33.78(22), H 2 O calc 10.25, total 98.25 (brighter domains). On the basis of 14 O atoms per formula unit (apfu) and (P+S) = 2 apfu, the darker and brighter domains have chemical formula Pb 1.00 (Fe 3+ 1.89 Al 0.97 ) Σ2.86 [P 1.57 S 0.43 O 7.43 (OH) 0.57 ][(OH) 5.58 (H 2 O) 0.42 ] Σ6.00 and Pb 0.98 (Fe 3+ 2.21 Al 0.53 ) Σ2.74 [P 1.51 S 0.49 O 7.49 (OH) 0.51 ][(OH) 5.18 (H 2 O) 0.82 ] Σ6.00 , respectively. Single-crystal X-ray diffraction was performed on a grain extracted from the same sample. Unit-cell parameters are a = 7.2191(10), c = 16.834(3) Å, V = 759.8(3) Å 3 and Z = 3; space group R $\bar{3}$ m . The crystal structure was refined on the basis of 226 unique reflections with F o > 4σ( F o ) and 31 least-square parameters to R 1 = 0.0415. Kintoreite is isotypic with other alunite-supergroup minerals. Micro-Raman spectroscopy suggests the possible occurrence of H 2 O groups, supporting the possible protonation of (OH) groups as a charge-balance mechanism in this mineral. Kintoreite may play an environmental role in the Alì area, where previous authors detected high concentrations of potentially toxic elements in soils.
Abstract The new mineral species ferrostalderite, CuFe2TlAs2S6, was discovered in the Lengenbach quarry, Binn Valley, Wallis, Switzerland. It occurs as minute, metallic, black, equant to prismatic crystals, up to 50 mu;m, associated with dolomite, realgar, baumhauerite (?) and pyrite. Minimum and maximum reflectance data for COM wavelengths in air are [λ (nm): R (%)]: 471.1: 24.2/25.4; 548.3: 23.7/24.7; 586.6: 22.9/23.8; 652.3: 21.0/22.0. Electron microprobe analyses give (wt.%): Cu 6.24(25), Ag 4.18(9), Fe 9.95(83), Zn 4.46(91), Hg 1.22(26), Tl 26.86(62), As 19.05(18), Sb 0.63(6),S 25.39(47), total 97.98(72). On the basis of 12 atoms per formula unit, the chemical formula of ferrostalderite is Cu 0.75(2) Ag 0.30(1) Fe 1.36(10) Zn 0.52(11) Hg 0.05(1) Tl 1.00(1) [As 1.94(4) Sb 0.04(1) ] ∑1.98(4) S 6.04(4) . The new mineral is tetragonal, space group I4̄2 m, with a = 9.8786(5), c = 10.8489(8) Å, V = 1058.71(11) Å 3 , Z = 4. The main diffraction lines of the calculated powder diagram are [d (in Å), intensity, hkl]: 4.092, 70, 211; 3.493, 23, 220; 3.396, 35, 103; 3.124, 17, 310; 2.937, 100, 222; 2.656, 19, 321; 2.470, 19, 400; 2.435, 33, 303. The crystal structure of ferrostalderite has been refined by Xray single-crystal data to a final R 1 = 0.050, on the basis of 1169 reflections with F0 > 4σ(F0). It shows a three dimensional framework of (Cu,Fe)-centred tetrahedra (1M1 + 2 M2), with channels parallel to [001] hosting disymmetric TlS 6 and (As,Sb)S3 polyhedra. Ferrostalderite is derived from its isotype stalderite M1 Cu M2 Zn 2 TlAs 2 S 6 through the homovalent substitution M2Zn2+ → M2Fe2+. The ideal crystal-chemical formula of ferrostalderite is M1 Cu M2 Fe 2 TlAs 2 S 6 .
Abstract Hakite-(Cd), hakite-(Fe) and hakite-(Zn) are new minerals belonging to the tetrahedrite group and forming, along with hakite-(Hg), the hakite series. They have been discovered in samples collected from the Bytíz deposit, in the uranium and base-metal Příbram ore district, Central Bohemia, Czech Republic. They occur as anhedral grains, up to 300 μm in size, in a calcite gangue, associated with clausthalite, cadmoselite, hakite-(Hg) [for hakite-(Cd)], berzelianite, bukovite, bytízite, crookesite, chaméanite, eskebornite, příbramite, the not yet approved giraudite-(Hg) and giraudite-(Cu) , hakite-(Hg), umangite, chalcopyrite, tetrahedrite-(Zn) and a new Cu–As selenide [for hakite-(Fe) and -(Zn)]. The three new species are black, with a metallic lustre. Mohs hardness is ca . 3½–4; calculated density is 6.019 (Hak-Cd), 6.011 (Hak-Fe) and 6.081 g.cm –3 (Hak-Zn). In reflected light, they are isotropic, pale grey with bluish (Hak-Cd) or brownish (Hak-Fe and Hak-Zn) shades. Empirical formulae of hakite-(Cd), hakite-(Fe), and hakite-(Zn) are Cu 9.71 Ag 0.24 Cd 1.51 Hg 0.43 Zn 0.03 (Sb 3.94 As 0.13 ) Σ4.07 Se 11.35 S 1.57 , Cu 10.11 Ag 0.18 Fe 0.81 Zn 0.50 Hg 0.26 (Sb 3.72 As 0.41 ) Σ4.13 Se 12.65 S 0.12 , and Cu 10.03 Ag 0.24 Zn 0.61 Fe 0.53 Hg 0.45 (Sb 3.55 As 0.60 ) Σ4.15 Se 12.82 S 0.08 , respectively. These formulae correspond to the end-member formulae Cu 6 (Cu 4 Cd 2 )Sb 4 Se 13 (Hak-Cd), Cu 6 (Cu 4 Fe 2 )Sb 4 Se 13 (Hak-Fe), and Cu 6 (Cu 4 Zn 2 )Sb 4 Se 13 (Hak-Zn). All these new members of the hakite series are cubic, I $\bar{4}$ 3 m , Z = 2, with unit-cell parameters a = 10.8860(6) Å, V = 1290.0(2) Å 3 (Hak-Cd); a = 10.7983(4) Å, V = 1259.12(14) Å 3 (Hak-Fe); and a = 10.8116(14) Å, V = 1263.8(5) Å 3 (Hak-Zn). These species are isotypic with the other members of the tetrahedrite group, and their crystal structures have been refined on the basis of single-crystal X-ray diffraction data down to R 1 values of 0.0230 (Hak-Cd), 0.0254 (Hak-Fe), and 0.0302 (Hak-Zn). These structural data allow us to describe the S-to-Se partitioning in hakite-series minerals and to understand the mechanisms avoiding too short Me –Se distances in these selenides.
The new mineral species oyonite, ideally Ag3Mn2Pb4Sb7As4S24, has been discovered in the Uchucchacua base-metal deposit, Oyon district, Catajambo, Lima Department, Peru, as very rare black metallic subhedral to anhedral crystals, up to 100 μm in length, associated with orpiment, tennantite/tetrahedrite, menchettiite, and other unnamed minerals of the system Pb-Ag-Sb-Mn-As-S, in calcite matrix. Its Vickers hardness (VHN100) is 137 kg/mm2 (range 132–147). In reflected light, oyonite is weakly to moderately bireflectant and weakly pleochroic from dark grey to a dark green. Internal reflections are absent. Reflectance values for the four COM wavelengths [Rmin, Rmax (%) (λ in nm)] are: 33.9, 40.2 (471.1); 32.5, 38.9 (548.3), 31.6, 38.0 (586.6); and 29.8, 36.5 (652.3). Electron microprobe analysis gave (in wt %, average of 5 spot analyses): Cu 0.76 (2), Ag 8.39 (10), Mn 3.02 (7), Pb 24.70 (25), As 9.54 (12), Sb 28.87 (21), S 24.30 (18), total 99.58 (23). Based on 20 cations per formula unit, the chemical formula of oyonite is Cu0.38Ag2.48Mn1.75Pb3.79Sb7.55As4.05S24.12. The main diffraction lines are (d in Å, hkl and relative intensity): 3.34 (−312; 40), 3.29 (−520; 100), 2.920 (−132; 40), 2.821 (−232; 70), 2.045 (004; 50). The crystal structure study revealed oyonite to be monoclinic, space group P21/n, with unit-cell parameters a = 19.1806 (18), b = 12.7755 (14), c = 8.1789 (10) Å, β = 90.471 (11)°, V = 2004.1 (4) Å3, Z = 2. The crystal structure was refined to a final R1 = 0.032 for 6272 independent reflections. Oyonite belongs to the Sb-rich members of the andorite homeotypic sub-series within the lillianite homologous series. The name oyonite is after the Oyon district, Lima Department, Peru, the district where the type locality (Uchucchacua mine) is located.
Abstract Tetrahedrite-(Cu), Cu 12 Sb 4 S 13 , has been approved as a new mineral species (IMA2022–078) from the Bankov magnesite deposit near Košice, Slovak Republic where it occurs as anhedral grains, up to 0.4 mm across, associated with skinnerite, chalcostibite, famatinite, tetrahedrite-(Fe) and zoned aggregates of tennantite-(Cu) to tennantite-(Fe). Tetrahedrite-(Cu) is steel-grey, with a metallic lustre. Mohs hardness is ca . 3½–4 and calculated density is 5.029 g.cm –3 . In reflected light, tetrahedrite-(Cu) is isotropic and grey with a bluish shade. Reflectance data for the four COM wavelengths in air are [λ (nm): R (%)]: 470: 31.1; 546: 30.1; 589: 29.9; and 650: 28.1. The empirical formula, based on electron-microprobe data (mean of 17 spot analyses), is Cu 11.42 Zn 0.26 Fe 0.19 (Sb 4.06 As 0.08 ) Σ4.14 S 12.99 . The ideal formula is Cu 6 (Cu 4 Cu 2 )Sb 4 S 13 , which requires (in wt.%) Cu 45.76, Sb 29.23 and S 25.01, total 100.00. Tetrahedrite-(Cu) is cubic, I $\bar{4}$ 3 m , with unit-cell parameters a = 10.3296(15) Å, V = 1102.2(5) Å 3 and Z = 2. Its crystal structure was refined by single-crystal X-ray diffraction data to a final R 1 = 0.0347 on the basis of 261 unique reflections with F o > 4σ( F o ) and 22 refined parameters. Tetrahedrite-(Cu) is isotypic with other tetrahedrite-group minerals. Previous findings of tetrahedrite-(Cu) are reported and some nomenclature issues, related to the Fe and Cu oxidation states, are discussed. At the Bankov deposit, tetrahedrite-(Cu) is related to hydrothermal, most probably Alpine, solutions strongly enriched in Cu, Sb and S.
Abstract Tennantite-(Hg), Cu 6 (Cu 4 Hg 2 )As 4 S 13 , was approved as a new mineral species (IMA2020-063) from the Lengenbach quarry, Imfeld, Binn Valley, Canton Valais, Switzerland. It was identified as an aggregate of black metallic tetrahedral crystals, less than 0.1 mm in size, intimately associated with sinnerite, and grown on realgar. In reflected light, tennantite-(Hg) is isotropic, grey in colour, with creamy tints. Minimum and maximum reflectance data for COM wavelengths in air are [λ (nm): R (%)]: 470: 29.1; 546: 29.1; 589: 28.5; 650: 27.7. Electron microprobe analysis gave (in wt.% – average of 7 spot analyses): Cu 32.57(42), Ag 6.38(19), Tl 0.29(14), Zn 0.04(5), Hg 17.94(2.27), Pb 0.70(51), As 17.83(61), Sb 0.34(8), S 24.10(41), total 100.19(1.04). The empirical formula of the sample studied, recalculated on the basis of Σ Me = 16 atoms per formula unit, is (Cu 4.69 Ag 1.04 Tl 0.03 ) Σ5.76 (Cu 4.35 Hg 1.58 Pb 0.06 Zn 0.01 ) Σ6.00 (As 4.20 Sb 0.05 ) Σ4.25 S 13.26 . Tennantite-(Hg) is cubic, I $\overline 4$ 3 m , with a = 10.455(7) Å, V = 1143(2) Å 3 and Z = 2. The crystal structure of tennantite-(Hg) has been refined by single-crystal X-ray diffraction data to a final R 1 = 0.0897 on the basis of 214 unique reflections with F o > 4σ( F o ) and 22 refined parameters. Tennantite-(Hg) is isotypic with other members of the tetrahedrite group. Mercury is hosted at the tetrahedrally coordinated M (1) site, in accord with the relatively long M (1)–S(1) distance (2.389 Å), similar to that observed in tetrahedrite-(Hg). Minor Ag is located at the triangularly-coordinated and split M (2) site. Other occurrences of tennantite-(Hg) are briefly reviewed and the Lengenbach finding is described within the framework of previous knowledge about the Hg mineralogy at this locality.
