抄録
Toyohaite, Ag2FeSn3S8, tetragonal, I41⁄a, a=7.464, c=10.80Å, Z=2, is a new mineral corresponding to the Ag analogue of rhodostannite. Microprobe analyses demonstrate partial substitutions of Cu for Ag and Zn for Fe. The most Ag-rich and poor analyses are: Ag 24.39, 16.31; Cu: 0.14, 5.15; Fe 6.28, 6.18; Zn 0.37, 1.29; Cd 0.22, 0.14; Sn 41.24, 42.01; In 0.05, 0.17; totals 100.86%, 99.65%. They correspond respectively to: (Ag1.95Cu0.02)Σ1.97(Fe0.97Zn0.05Cd0.02)Σ1.04Sn2.99S7.57, and (Ag1.26Cu0.68) Σ1.94(Fe0.92Zn0.16Cd0.01) Σ1.09(Sn2.95In0.01) Σ2.96S7.39 (basis: total metal=6). Calculated density is 4.94 g/cm3. Toyohaite has a rhodostannite-like brown reflection color with very weak dichroism and distinct to strong anisotropism. Reflectances are: 23.5–24.3% (480nm); 24.1–26.1% (546nm) 24.7–26.4% (589nm); 26.5–28.3% (650nm). X-ray powder diffraction lines and their relative intensities: 3.72(35), 3.21(100), 2.03(35) and 1.882(35). It occurs as irregular-shaped poly crystalline aggregates up to 200 μm across in a massive pyrite-sphalerite ore from the Sorachi vein of the Toyoha mine, Sapporo, Hokkaido, Japan. The intimate associates include rhodostannite, hocartite, teallite, herzenbergite, and berndtite.
