抄録
The modes of occurrence, optical properties, X-ray diffraction data, physical properties, and chemical composition of arsenian hauchecornite from the Tsumo mine were described. The mine is one of the pyrometasomatic ore deposits in the Sangun metamorphic terrain, Southwestern Japan. The present hauchecornite is the first finding in Japan.
The mineral is found in bornite-chalcopyrite ore at Maruyama deposit of the Tsumo mine and associated intimately with bornite, chalcopyrite, and sphalerite, and accompanied by a mineral of linnaeite series, sometimes, with small amounts of native gold, tetradymite, stannoidite, mawsonite, native bismuth, and an unknown mineral of Cu–Ag–S system.
Grain size of the mineral is generally in the range from 0.05 to 0.7 mm across. Reflection colour is pinkish white with yellowish tint and a little lighter than that of pyrrhotite. Reflectance values are 40.0–44.6% (470 nm), 44.3–49.3 nm (546 nm), 46.2–51.1% (589 nm), 48.2–53.3% (650 nm). Microhardness value is 435–516 kg/mm2.
The mineral is tetragonal, a0=14.56±0.01Å, c0=10.87±0.01Å, Z=8, cell volume 2295.2±3.0Å3, calculated specific gravity 6.62 g/cm3. Chemical composition determined with the electron probe microanalyser is as follows: Ni 45.02, Fe 0.42, Co 0.57, Bi 26.43, As 4.19, Sb 0.46, Te 0.19, S 22.25, total 99.51 wt.%. Empirical formula is (Ni8.80Fe0.09Co0.10)Σ8.99(Bi1.46As0.64Sb0.04Te0.02)Σ2.16S8.00 on the basis of S=8.
