ＥＰＭＡによるルゾナイト‐ファマチナイト系鉱物の化学組成に関する検討

Abstract

To reconfirm whether minerals of luzonite-famatinite series form complete solid solution between them as Springer (1969) reported or limited solid solution having immiscibility gap from approximately 10 to 40 mol% Cu3SbS4 as Skinner (1960) inferred. 16 samples of luzonite and famatinite from 7 mines in Japan, Formosa and Philippines were examined by electron probe microanalyser (EPMA). The quantitative analytical data by EPMA for the samples are given in Tables 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 and 13. The specimens from the Hokuetsu mine, Japan and the Mankayan mine, Philippines have most nearly stoichiometric composition of luzonite as from 0 to 3 mol% Cu3SbS4. They from the Lobo mine, Philippines and the Kinkaseki mine, Formosa have from 2 to 12 mol% Cu3SbS4, and from 2 to 7 or 36 to 41 mol% Cu3SbS4 in composition, respectively. Also luzonite-famatinite series minerals from the Teine, Kasuga and Akeshi mines, Japan have compositions of such wide range as from 19 to 71, 26 to 82 and 3 to 78 mol% Cu3SbS4, respectively. However, the composition corresponding to stoichiometric Cu3SbS4 of famatinite was not found during this study. Analytical data for 378 points in 16 specimens are summarized as shown in Fig. 5, and it is found that there is existance of minerals having continuous compositions between luzonite and famatinite except nearly famatinite end. Therefore it is concluded that the complete solid solution between them exists at low temperature as the result of Springer's examination.