Bulk compositions of intimate intergrowths of chalcopyrite and sphalerite and their genetic implications

An Unusual Texture: Skeletal Sphalerite in Pyrite from Dajing Tin‐polymetallic Deposit, China

“…Skeletal sphalerite with stellar, cruciform to snowflake-like (or cauliflower-like) shapes included in chalcopyrite is frequently seen among different types of sulfide deposit. Such kind of texture has been often studied and discussed from various viewpoints such as crystallography, experimentation, chemical composition and genesis by mineralogists and economic geologists because of its mineralogical significance (Sugaki and Tashiro, 1957;Firsov, 1961;Aoki, 1971;Sugaki et al, 1987;Marignac, 1989). Sphalerite with a peculiar texture of stellar, cruciform to snowflake-like shapes included in pyrite is widely found in the Dajing tinpolymetallic deposit, North China, which has not been reported in previous works, as far as the present authors know.…”

“…The temperature of unmixing of sphalerite from chalcopyrite is estimated from high-temperature dissolution experiments to be on the order of 400°C or higher (Buerger, 1934;Sugaki and Tashiro, 1957). Sugaki et al (1987) concluded that the star-like sphalerites in chalcopyrite are exsolution products derived from primary chalcopyrite solid solution and/or zincic iss at above 400°C, considering the bulk chemical composition of chalcopyrite with sphalerite star. As supporting this exsolution hypothesis, the occurrence of sphalerite skeletal crystal in chalcopyrite has been widely noticed in the deposits of "meso-to hypo-thermal" types (Kelly and Turneaure, 1970;Grant et al, 1977;Kelly and Rye, 1979;Waal and Johnson, 1981).…”

Polymetallic Mineralization at the Nakakoshi Copper Deposits, Central Hokkaido, Japan

“…vol.49, no.2, 1999 95 Polymetallic Mineralization at the Nakakoshi Copper Deposits, Central Hokkaido The sphalerite star is common in the Stage II chalcopyrite, which may have been exsolved from chalcopyritesphalerite solid solution at higher temperature conditions. Hydrothermal synthetic experiments suggest that maximum solubilities of Zn in chalcopyrite are 1.3 wt% (0.9 atm%), 1.1 wt% (0.8 atm%), and 1.0 wt% (0.7 atm%) at 500, 400 and 300 o C under 500 Kgf/cm 2 pressure, respectively (Sugaki et al, 1987). The modal amount of the sphalerite star in chalcopyrite at Nakakoshi is 1.4 vol % which corresponds to the bulk Zn content of 1.0 wt% (0.7 atm %).…”

Isocubanite, a New Definition of the Cubic Polymorph of Cubanite CuFe2S3

“…Zn-bearing isocubanite is most probably replaced by chalcopyrite containing minute starshaped exsolutions of sphalerite (Oudin and Constantinou, 1984;Sugaki et al, 1987) in fossil ores.…”

“…509 514 (Q Copyright the Mineralogical Society 1962Yund and Kullerud, 1961). It is frequently mentioned in the literature as iss, 'intermediate solid solution of CuFeZS3 composition' (Amcoff, 1981;Barton, 1973;Cabri, 1973;Kojima and Sugaki, 1984;Sugaki et al, 1975). It was apparently first reported by Ramdohr (1928) and then by Odman (1933) under the name of cubanite II.…”