Occurrences, chemical compositions and crystallization process of silver minerals and ore minerals in Onan district, Shimane Prefecture, Japan

Abstract

Occurrence and chemical compositions of ore minerals and Ag-bearing minerals in Kuki mine, Onan, Shimane, have been investigated to clarify the mineralization process and to characterize silver mineralization. Three modes of occurrences of Ag mineral were observed: native silver and pyragyrite occur within minute cavities in the first generation pyrite; argentite and silver particles of sub-micron scale distribute around the minute cavities in pyrite; native silver occur within minute cavities in sphalerite. Au-mineralization is recognized only in pyrite and arsenopyrite. Two stages defined by the assemblage of pyrite and arsenopyrite, and by associated silver and gold mineralization are recognized.