Small size, high value: composition and manufacture of second millennium AD copper-based beads from northern Zimbabwe

Abstract

This investigation introduces a new dimension to the previous typological analyses of the metal bead assemblages from Zimbabwean archaeological sites. Here we present the microstructural and chemical characterisation of 50 copper-based metal beads from the collections of the Zimbabwe Museum of Human Sciences (ZMHS) in Harare, most of them from Later Farming Community period sites in northern Zimbabwe (AD 1000 to AD 1900). The analytical study employed optical microscopy, ED-XRF and SEM-EDS. Compositionally, unalloyed copper, arsenical copper and tin bronzes were identified in the earlier sites, with some significant regional variations. From the seventeenth century, brass becomes the preferred alloy. The potential sources of these metals and their spatial and temporal patterning are discussed with reference to both the socio-economic dynamics prevailing in Zimbabwe during the period, and the symbolic value of metal beads in these communities. The metallographic study showed a preponderance of wrought beads, with a small but significant presence of cast forms. These fabrication technologies reflect little outside influence and are in line with indigenous African metal smithing methods.