Mineral of the composition CuFe2S4 from sulfide copper-nickel ores of the Lovnoozerskoe deposit (Kola Peninsula)
Orsoev D. A., Kanakin S. V., Pakhomovsky Ya. A., Ushchapovskaya Z. F., Reznitsky L. Z.
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2015. V. 144. N 3. P. 70-81
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Language: Russian
Abstract
The unnamed mineral CuFe2S4 has been found in sulfide Cu-Ni ores of the Lovnoozerskoe deposit in the Kola Peninsula (Russia). It occurs in the norite composed of orthopyroxene (bronzite), Ca-rich plagioclase (66 % An), pargasite and phlogopite; the later minerals are represented by talc, chlorite and carbonates, and associated ore minerals such as monoclinic pyrrhotite, pentlandite, chalcopyrite and pyrite. CuFe2S4 is located mainly in chalcopyrite, probably replacing it, and occurs in later carbonate veinlets together with re-deposited sulfides. Its color is light-yellow with brownish tint; luster is metallic. Mohs hardness 5—5.5; VHN 654 86 kgs/mm2. Density (calc.) = 4.524 g/cm3. The mineral is anisotropic, internal reflections are absent. Reflectance values (l, nm R’g and R’p %) are: 440 30.3 29.5, 500 43.7 42.8, 560 50.9 49.6, 620 52.4 51.2, 640 52.6 51.4, 680 52.8 51.6, 700 52.7 51.4. CuFe2S4 is monoclinic, a = 6.260(4) Å, b = 5.39(1) Å, c = 13.19(1) Å, b = 94.88(7)°, V = 443(1) Å3, Z = 4. Strongest lines of the powder diffraction pattern [d, Å (I)(hkl)] are: 4.150 (10) (012); 3.559 (4) (112); 3.020 (4) (104); 2.560 (3) (212); 2.500 (3) (105); 2.340 (3) (122); 1.817 (3) (215); 1.489 (3) (402). Chemical composition (wt %): Cu 20.44, Fe 35.85, Ni 0.65, Co 0.14, S 43.15, total 100.23. Empirical formula (based on the sum of 7 apfu) is Cu0.969(Fe1.934Ni0.034Co0.007)1.975S4.056. According to its occurrence conditions, the mineral was formed in result of low temperature processes involving metamorphogenic-hydrothermal solutions.
Key words: mineral CuFe2S4, copper-nickel ore, norite, sulfide minerals, Kola Peninsula.
