There are two main areas in sub-Saharan Africa that feature prominently in glass studies: East Africa and South Africa. Unfortunately, there are not very many people looking at glass in sub-Saharan Africa and I haven’t actively searched for material related to sub-Saharan glass in several years, making these entries far less informative than some of my other regional summaries. Eventually I plan to do a little more digging and see if I can add more information, but this is what I have at the moment.
I only know of two studies concerning glass in East Africa, one in Zanzibar, Tanzania and one comparing sites in Kenya to others in South Asia (which appears in two publications, but is essentially the same study). The study in Tanzania focuses on classification and typologies of glass beads, while the study on Kenyan material focuses on chemical analysis.
Both studies only examine beads. The study from Zanzibar includes comparisons to non-glass beads, but the study in Kenya focuses solely on glass beads. My understanding is that beads form the primary body of glass material from this region.
As I said above, one study focuses on Zanzibar, Tanzania, but also looks at beads from a range of other sites (Dakar, Sofala, Kilwa Kisiwani, Dar es Salaam, Bagamoyo, Pemba, Mombasa, and Gedi). The focus, however, is on Zanzibar. The other study looks at four sites in Kenya (Mtwapa, Bungule, Muasya, and Ungwana). Chronologically, the study of beads at Zanzibar range from the 1st through 15th centuries, which is an enourmous range of time. The Kenyan study looks at beads from the 9th to 19th centuries, which is almost equally enourmous. Given the scarcity of studies and the range of chronology, any comparison of this material is going to be problematic.
Both studies discuss the differences between the winding and drawing methods of making glass beads. The Zanzibar study mentions that segmented beads could be made by taking a bit of iron and hand-drawing the segments rather than using a mould. This isn’t necessarily a new idea (though it may have been at the time), but it is good to keep in mind.
Only the Kenyan study could look at chemistry, since the technology was still in its infancy at the time of the study in Zanzibar. In Kenya, most of the glass is m-Na-Al (silica-soda-alumina) rather than m-Na-Ca or v-Na-Ca (silica-soda-lime) like we see in Roman, Egyptian, and Middle Eastern contexts. This is a very different recipe from European and Middle Eastern areas and suggests that the technology for the glass found in East Africa developed separately. The Kenyan glass also differs from earlier South Asian glass in that it has higher uranium and lower barium contents.
Unfortunately, there is too little evidence and research coming out of East Africa to suggest that the glass was made there, despite the relative uniqueness of the glass chemistry. Instead, this difference in trace elements may be a consequence of the Kenyan material dating to much later than the analysed South Asian material. A later study of the same material found similarities between the Kenyan glass and contemporary finds along the west coast of India, but there is still no evidence for where the glass would have been made. It is clear that some form of exchange occurred, but we cannot say whether it was from Kenya to India, India to Kenya, or some third party to both.
Moving off of that point, most of these sites date to much later periods, well into the age of exploration, colonisation, and conquest by numerous groups (not just Europeans). Therefore, the source of these beads need not be Kenyan or Indian at all. Unfortunately, the material hasn’t been compared to other contemporary finds in this region and therefore our ability to speak about it is limited.
Dussubieux, L., B. Gratuze, and M. Blet-Lemarquand
2010 Mineral-Soda-Alumina Glass: Occurrence and Meaning. Journal of Archaeological Science 37(7): 1646-1655.
Dussubieux L., C.M. Kusimba, V. Gogte, S.B. Kusimba, B. Gratuze, and R. Oka
2008 The Trading of Ancient Glass Beads: New Analytical Data from South Asian and East African Soda-Alumina Glass Beads. Archaeometry 50(5): 797-821.
Van der Sleen, WGN
1958 Ancient Glass Beads with Special Reference to the Beads of East and Central Africa and the Indian Ocean. Journal of the Royal Anthropological Institute of Great Britain and Ireland 88(2)203-216.