On the basis of a mineralogical, petrological and chemical study of a “greenstone” complex intercalated in a phyllitic formation in the Western Peloritani Mountains, two main rock types can be distinguished: amphibole-chlorite metabasite (with traces of an old generation of glaucophane), and albite metabasite. The two rock types show considerable differences in composition, a consequence of sodium metasomatism. The study indicates that the greenstone complex is a metaspilite.