Tennantite-(In), Cu6(Cu5In)As4S13, was approved as a new mineral species from the Pefka epithermal ore deposit, Alexandropouli, Evros, Western Thrace, Greece. It was identified as anhedral grains, up to 0.1 mm in size, intimately associated with roquesite, galena, and tennantite-(Fe) in quartz gangue. In reflected light, tennantite-(In) is isotropic, pale grey in color. Reflectance values for the four COM wavelengths in air are λ (nm): R (%)]: 470: 31.2; 546: 30.7; 589: 30.5; 650: 28.8. Electron microprobe analysis gave (in wt% - average of 7 spot analyses): Cu 43.83(95), Mn 0.22(8), Fe 0.65(46), Zn 0.57(12), Cd 0.16(5), Pb 0.26(2), As 14.38(3.00), In 5.05(59), Sb 7.74(3.08), Te 0.48(9), S 26.18(79), total 99.52(78). The empirical formula of the studied sample, recalculated on the basis of ΣMe = 16 atoms per formula unit, is Cu10.82In0.69Fe0.18Zn0.14Mn0.06Cd0.02Pb0.02As3.01Sb1.00Te0.06S12.81. Tennantite- (In) is cubic, I 4 3m, with a = 10.285(2) Å, V = 1088.1(6) Å3, Z = 2. The five strongest reflection lines in the calculated powder X-ray diffraction pattern are [d in Å, I, hkl]: 2.969, 100, 222; 2.571, 20, 400; 1.878, 7, 521; 1.818, 42, 440; and 1.551, 21, 622. The crystal structure of tennantite-(In) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.0253 on the basis of 240 unique reflections with Fo > 4σ (Fo) and 23 refined parameters. Tennantite-(In) is isotypic with other members of the tetrahedrite group. Indium is hosted at the tetrahedrally coordinated M(1) site, in accord with the known preference of this element for tetrahedrally coordinated bonding environments. © 2025 The Author(s). Published by Cambridge University Press on behalf of The Mineralogical Society of the United Kingdom and Ireland.
Tennantite-(In), Cu6(Cu5In)As4S13, a new member of the tetrahedrite group from Pefka, Greece
Biagioni Cristian;Musetti Silvia;Konstantinos Mavrogonatos
2025-01-01
Abstract
Tennantite-(In), Cu6(Cu5In)As4S13, was approved as a new mineral species from the Pefka epithermal ore deposit, Alexandropouli, Evros, Western Thrace, Greece. It was identified as anhedral grains, up to 0.1 mm in size, intimately associated with roquesite, galena, and tennantite-(Fe) in quartz gangue. In reflected light, tennantite-(In) is isotropic, pale grey in color. Reflectance values for the four COM wavelengths in air are λ (nm): R (%)]: 470: 31.2; 546: 30.7; 589: 30.5; 650: 28.8. Electron microprobe analysis gave (in wt% - average of 7 spot analyses): Cu 43.83(95), Mn 0.22(8), Fe 0.65(46), Zn 0.57(12), Cd 0.16(5), Pb 0.26(2), As 14.38(3.00), In 5.05(59), Sb 7.74(3.08), Te 0.48(9), S 26.18(79), total 99.52(78). The empirical formula of the studied sample, recalculated on the basis of ΣMe = 16 atoms per formula unit, is Cu10.82In0.69Fe0.18Zn0.14Mn0.06Cd0.02Pb0.02As3.01Sb1.00Te0.06S12.81. Tennantite- (In) is cubic, I 4 3m, with a = 10.285(2) Å, V = 1088.1(6) Å3, Z = 2. The five strongest reflection lines in the calculated powder X-ray diffraction pattern are [d in Å, I, hkl]: 2.969, 100, 222; 2.571, 20, 400; 1.878, 7, 521; 1.818, 42, 440; and 1.551, 21, 622. The crystal structure of tennantite-(In) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.0253 on the basis of 240 unique reflections with Fo > 4σ (Fo) and 23 refined parameters. Tennantite-(In) is isotypic with other members of the tetrahedrite group. Indium is hosted at the tetrahedrally coordinated M(1) site, in accord with the known preference of this element for tetrahedrally coordinated bonding environments. © 2025 The Author(s). Published by Cambridge University Press on behalf of The Mineralogical Society of the United Kingdom and Ireland.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
