TY - JOUR

T1 - Tarutinoite, Ag3Pb7Bi7S19, a new member of the lillianite homologous series from the Tarutinskoe copper-skarn deposit, Southern Urals, Russia

AU - Kasatkin, Anatoly V.

AU - Biagioni, Cristian

AU - Nestola, Fabrizio

AU - Škoda, Radek

AU - Gurzhiy, Vladislav V.

AU - Agakhanov, Atali A.

AU - Kuznetsov, Aleksey M.

PY - 2025/8/20

Y1 - 2025/8/20

N2 - The new mineral tarutinoite, ideally Ag 3 Pb 7 Bi 7 S 19 , was found in a fragment of a drill core extracted at the 178.5 m level of borehole #4604 at the Tarutinskoe (Tarutino) copper-skarn deposit, Chelyabinsk Oblast, Southern Urals, Russia. It occurs as anhedral grains up to 0.10 × 0.05 mm intergrown with hessite and galena in magnetite and calcite. Tarutinoite is grey, opaque with metallic lustre, brittle tenacity and uneven fracture. No cleavage and parting are observed. The Vickers’ micro-indentation hardness (VHN, 25 g load) is 178 kg/mm 2 (range 165–194, n = 4), corresponding to a Mohs’ hardness of 3.5–4, and calculated density is 7.180 g/cm 3 . In reflected light, tarutinoite is greyish-white, very weakly bireflectant and non-pleochroic. Under crossed polarisers the new mineral exhibits moderate anisotropy, in grey and dark grey tones with bluish tints. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are ( R min / R max , %): 45.5/47.9 (470 nm), 43.5/45.0 (546 nm), 43.3/44.1 (589 nm) and 41.8/42.5 (650 nm). The chemical composition (wt.%, electron microprobe data, mean of 7 spot analyses) is Cu 0.30, Ag 8.33, Cd 0.04, Pb 37.12, Bi 37.52, S 15.15, Se 0.40, Te 0.66, total 99.52. The empirical formula calculated on the basis of 36 atoms per formula unit is (Ag 3.01 Cu 0.18 ) Σ3.19 (Pb 6.98 Cd 0.01 ) Σ6.99 Bi 7.00 (S 18.42 Se 0.20 Te 0.20 ) Σ18.82 . Tarutinoite is monoclinic, space group C 2/ m , with a = 13.5447(12), b = 4.1027(3), c = 32.481(4) Å, β = 96.433(9)°, V = 1793.6(3) Å 3 and Z = 2. The strongest lines of the powder X-ray diffraction pattern [ d , Å ( I , %) ( hkl )] are: 16.15 (48) (0 0 2), 3.407 (69) (1 1 –5), 3.328 (95) (2 0 –9), 3.042 (65) (2 0 –10), 2.941 (100) (3 1 2), 2.910 (55) (3 1 –4), 2.053 (44) (0 2 0). The crystal structure of tarutinoite was refined to R 1 = 0.1349 for 2024 reflections with F o > 4σ( F o ) and 84 refined parameters. The new mineral is the first 7,8 L member of the lillianite homologous series. It is named after its type locality.

AB - The new mineral tarutinoite, ideally Ag 3 Pb 7 Bi 7 S 19 , was found in a fragment of a drill core extracted at the 178.5 m level of borehole #4604 at the Tarutinskoe (Tarutino) copper-skarn deposit, Chelyabinsk Oblast, Southern Urals, Russia. It occurs as anhedral grains up to 0.10 × 0.05 mm intergrown with hessite and galena in magnetite and calcite. Tarutinoite is grey, opaque with metallic lustre, brittle tenacity and uneven fracture. No cleavage and parting are observed. The Vickers’ micro-indentation hardness (VHN, 25 g load) is 178 kg/mm 2 (range 165–194, n = 4), corresponding to a Mohs’ hardness of 3.5–4, and calculated density is 7.180 g/cm 3 . In reflected light, tarutinoite is greyish-white, very weakly bireflectant and non-pleochroic. Under crossed polarisers the new mineral exhibits moderate anisotropy, in grey and dark grey tones with bluish tints. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are ( R min / R max , %): 45.5/47.9 (470 nm), 43.5/45.0 (546 nm), 43.3/44.1 (589 nm) and 41.8/42.5 (650 nm). The chemical composition (wt.%, electron microprobe data, mean of 7 spot analyses) is Cu 0.30, Ag 8.33, Cd 0.04, Pb 37.12, Bi 37.52, S 15.15, Se 0.40, Te 0.66, total 99.52. The empirical formula calculated on the basis of 36 atoms per formula unit is (Ag 3.01 Cu 0.18 ) Σ3.19 (Pb 6.98 Cd 0.01 ) Σ6.99 Bi 7.00 (S 18.42 Se 0.20 Te 0.20 ) Σ18.82 . Tarutinoite is monoclinic, space group C 2/ m , with a = 13.5447(12), b = 4.1027(3), c = 32.481(4) Å, β = 96.433(9)°, V = 1793.6(3) Å 3 and Z = 2. The strongest lines of the powder X-ray diffraction pattern [ d , Å ( I , %) ( hkl )] are: 16.15 (48) (0 0 2), 3.407 (69) (1 1 –5), 3.328 (95) (2 0 –9), 3.042 (65) (2 0 –10), 2.941 (100) (3 1 2), 2.910 (55) (3 1 –4), 2.053 (44) (0 2 0). The crystal structure of tarutinoite was refined to R 1 = 0.1349 for 2024 reflections with F o > 4σ( F o ) and 84 refined parameters. The new mineral is the first 7,8 L member of the lillianite homologous series. It is named after its type locality.

UR - https://www.mendeley.com/catalogue/97b6d6e4-5374-30d1-9202-a198a4101502/

U2 - 10.1180/mgm.2025.1

DO - 10.1180/mgm.2025.1

M3 - Article

VL - 89

SP - 483

EP - 491

JO - Mineralogical Magazine

JF - Mineralogical Magazine

SN - 0026-461X

IS - 4

ER -