Unravelling the glass trade bead sequence from Magoro Hill, South Africa: separating pre-seventeenth-century Asian imports from later European counterparts

Abstract

Excavations conducted between 2010 and 2012 at Magoro Hill, a site in South Africa's Limpopo Province frequented or intermittently occupied by African farming communities since the first millennium AD, yielded a substantial glass bead assemblage. A selection of the beads was studied non-destructively by classifying them according to morphological attributes, supplemented by Raman analyses and XRF measurements. It became evident that a morphological classification of beads recovered from sites that include imports into Africa after the seventeenth century AD could be problematic due to apparent morphological similarities between earlier and later beads. This paper demonstrates the use and archaeological application of Raman and XRF measurements to separate earlier imported beads from later counterparts by identifying glass nanostructure, as well as pigments and opacifiers, which were not used in bead series pre-dating the seventeenth century AD. Results obtained from Raman and XRF measurements indicate that although some beads retrieved from Magoro Hill pre-date the seventeenth century and belong to the Indo-Pacific (K2, East Coast, Khami) and Zimbabwe series, the largest number of beads is from a later European origin. This ties in with the settlement history of the site, which suggests that it primarily served as a rendezvous for episodic rainmaking rituals before it became the stronghold and capital of a Venda chiefdom, headed by the Magoro dynasty, in the second half of the eighteenth century AD. The comparative analysis of the long bead sequence sheds new light on changing patterns in the availability, range, consumption and origin of glass trade beads imported into the northern interior of South Africa over a period of about 1000 years.

Non-invasive Raman analyses of Chinese huafalang and related porcelain wares. Searching for evidence for innovative pigment technologies

“…The more reasonable assumption may be that arsenic arises from the cobalt ores [45,46,80,81]. Eighteen century European porcelains made with European cobalt ores exhibit the same Raman signature as shown in refs [45,46,77,80,81], but also in some Limoges enamels [82] and glass beads [83][84][85] produced during the 17 th and 18 th century. The cobalt ores come from Erzgebirge mountains between Saxony and Bohemia and contain a high level of arsenic (As/Co ~ 0.1-0.2) [83][84][85][86], which may explain the formation of lead arsenate in the blue enamel.…”

“…The Raman signature of lead arsenate is very strong because the high number of electrons involved in the As-O bond. This peak is observed between 810 and 830 cm -1 [67,76] in many coloured areas, in blue huafalang G 5250 (Fig. 4) and G 3361 (Fig.…”

The Chronology of Insiza Cluster Khami‐Phase Sites in South‐Western Zimbabwe: Compositional Insights from pXRF and Raman Analysis of Excavated Exotic Glass Finds

“…A portable Niton Thermo Scientific XL3t GOLDD was used for XRF analysis of the beads (for further details, see Koleini et al . ). The samples are examined using fundamental calibration parameters used in mining Cu/Zn mode.…”

“…The results are then compared to archaeological sites elsewhere in Zimbabwe (Baranda), Botswana (Basinghal Farm) and South Africa (Magoro Hill) where similar bead series have been recovered (Koleini et al . ,b, ).…”

“…Recent studies of glass beads conducted with the aid of a combination of pXRF and Raman spectroscopy have demonstrated the efficiency of these mobile techniques in defining the chronological sequences of traded glass bead series in southern Africa (Koleini et al . ,b; ,b). Following the method reported in Koleini et al .…”