An amphibolite-facies mica schist carrying syngenetic copper mineralisation has been mapped over a strike length of 2.5 km near Williamstown, 40 km North East of Adelaide, South Australia. The schist, termed the Ukaparinga Schist, contains disseminated chalcopyrite at depth, whereas at and near the surface secondary copper carbonates and cupriferous hydrobiotite have formed. The average copper content of 1520 percussion drill samples of the Ukaparinga Schist (near surface oxidised material) is 0.33% and the average copper content of 365 diamond drill samples (primary mineralisation) is 0.27% cu. Adjacent beds generally contain less than 50 ppm copper. The confinement of the copper mineralisation to the Schist and its absence from adjacent beds, together with the disseminated nature of the mineralisation and the rarity of veins and cross cutting relationships, indicate that the copper is of syngenetic origin. In respect of its syngenetic origin and grade of metamorphism the Ukaparinga Schist resembles the copper mineralised Kanmantoo Group schists at Kanmantoo South Australia, however, the two deposits are of different ages, the age of the Kanmantoo Group being Cambrian and that of Ukaparinga Schist being Upper Precambrian (Adelaidean).