Ishiharaite, (Cu,Ga,Fe,In,Zn)S, a new mineral from Capillitas Mine, northwestern Argentina

MÁRQUEZ-ZAVALÍA M.F.; GALLISKI M. A.; DRABEK; VYMAZALOVÁ A.; WATANABE Y.; MURAKAMI H.; BERHARDT J.

CANADIAN MINERALOGIST

MINERALOGICAL ASSOC CANADA

Lugar: Toronto, Canada; Año: 2014

0008-4476

Ishiharaite is a new sulfide mineral, (Cu,Ga,Fe,In,Zn)S, discovered at the NuevaEsperanza vein, Capillitas mine (27°27´S, 66°30´W) an epithermal ore depositbelonging to the Farallón Negro Mining District, northwestern Argentina. The mineraloccurs as subhedral, equidimensional, individual grains (20 to 50 μm in size), includedin tennantite. It is a dark gray metallic mineral, opaque and non fluorescent. Under thepolarizing-light microscope, using reflected light, it is an isotropic mineral, and its coloris burgundy brown with a faint violet hue in air and violet-burgundy in oil. The mainreflectance values are (Rair,Roil - λ/nm): 18.27,6.77 - 470; 20.10,7.91 - 546; 21.74,8.96- 589 and 23.94,10.44 - 650. Ishiharaite is cubic, space group F 3m, a = 5.368(1) Å, V= 154.68(1) Å3, Z = 4. The strongest five X-ray powder-diffraction lines [d in Å (I)(hkl)]are: 3.096 (100) (111); 1.897 (60) (220); 1.620 (40) (311); 2.684 (20) (200); 1.097(15)(422). Electron-microprobe analyses of the natural grains (n=22) give an averagecomposition (wt.%) of: S 30.77, Cu 33.61, Ga 13.31, In 9.48, Zn 5.74, Fe 6.13; theaverage (n=6) chemical composition of the synthetic phase is: S 30.73, Cu 28.05, Ga15.99, In 11.86, Zn 7.37, Fe 6.13. The empirical formula of the mineral and syntheticanalogue, based on 2 apfu, are: (Cu0.54Ga0.19Fe0.12In0.08Zn0.09)Σ1.02S0.97, and(Cu0.45Ga0.24Fe0.11In0.11Zn0.11)Σ1.02S0.98, respectively. The mineral (IMA No.2013-119) is named in honor of Dr. Shunso Ishihara (b. 1934), Emeritus Advisor ofAIST (Advanced Industrial Science and Technology), Tsukuba, Japan.