Under the glaucophanitic metamorphic conditions, stilpnomelane appears in schists whose grade ranges from the pumpellyite zone to the biotite zone. The parageneses of stilpnomelane in these schists are rather simple, and the mineral is associated commonly with quartz, chlorite and calcite and rarely with epidote, pumpellyite and actinolite. The apparent wide range of chemical and mineralogical compositions of stilpnomelane-bearing schists is due to small-scale heterogeneity of rocks, but not due to their suitable bulk chemical composition.

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Awaruite was found in serpentinized peridotites from the Mineoka district, southern Boso Peninsula. The mineral occurs invariably in serpentinized parts of the rocks, indicating that it was formed in the course of serpentinization. Heazlewoodite and native copper were formed also in association with awaruite during serpentinization. Chemical analysis of the awaruite yields the formula: Ni_2.26 Fe. Native copper associated with heazlewoodite contains about 5 weight percent nickel. The occurrence of awaruite suggests that oxygen fugacity of fluid being responsible to serpentinization was lowered at least locally down to 10^-42 bar during serpentinization. The low oxygen fugacity of fluid was resulted from reaction between fluid and fayalite component of olivine producing magnetite and serpentine minerals.

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The Shin-yama pyrometasomatic ore deposit is characterized by the ubiquitous distribution of Fe-S-O minerals and by the zoning of the mineral associations. Ore specimens collected from the deposit were exmained for mineral constitution and ore textures. Fe-S minerals include troilite, hexagonal pyrrhotite, monoclinic pyrrhotite, and pyrite; hexagonal pyrrhotite ranges in composition from 47.3 to 47.7 atomic percent Fe. As for Fe-O minerals, magnetite is overwhelmingly dominant, and hematite is found in a limited area only. Pyrrhotite found in the iron ore zone almost always belongs to the monoclinic type. In the copper ore zone, hexagonal, and monoclinic pyrrhotites are dominantly distributed in the ore shoot, and in the periphery of an ore body respectively. Although Fe-S-O minerals in an assemblage seem to be thermodynamically compatible with one another, the ore textures indicate that they were sequentially formed in the order of, magnetite, hexagonal pyrrhotite, monoclinic pyrrhotite, and pyrite. Metallization overlapped with the hydration-reconstruction of skarn was developed at the temperatures decreasing from 390°C to less than 315°C.

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