Morphological and compositional analysis of glass beads from three shipwrecks in the Indian Ocean world has increased our understanding of the chronology and distribution of mid-fifteenth to mid-seventeenth century glass.

In a recent article, Kunz and Mills (2021) report 10 drawn, a speo finished, turquoise blue, IIa40 beads manufactured in Venice and recovered from three late precontact sites in the Alaskan Arctic. They argue that these beads date to the fifteenth century, predating Columbus's arrival in the Americas. This conclusion is certainly in error because beads of this type were not manufactured prior to approximately AD 1560. The historical and archaeological evidence for this dating is substantial. Additionally, the elemental and radiocarbon evidence presented by Kunz and Mills (2021) supports a late sixteenth- to early seventeenth-century date for these beads.

This report focuses on the morphometric and elemental analysis of glass beads collected from an adobe structure (CA-SCR-217H-T) at Mission Santa Cruz, which operated between 1791 and the 1830s in the colonial province of Alta (upper) California. Previous chemical research established a chronological framework for opacified beads collected from sites in Canada, the Great Lakes region, and the southeastern United States. Testing the viability of this chronological framework for California, we analyzed 100 white glass beads using a conventional typology and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS)—the first application of LA-ICP-MS to a California mission. We present the results of the LA-ICP-MS study and then briefly comment on the potential for LA-ICP-MS to refine chronologies associated with colonial missions and other postcontact sites.

The glass bead trade in southern Africa provides important evidence of interregional contact during the early modern period. Compositional analysis of a large assemblage of imported glass beads from the sixteenth- to seventeenth-century AD trading site of Baranda in northern Zimbabwe reveals a south Asian origin of the majority of the beads. Combining stratigraphic data and morphological analysis with innovative compositional XRF and Raman spectroscopy approaches, the research was able to assign the Baranda beads accurately to their correct chronological range. This coincides with the period of Portuguese dominance of Indian Ocean trade.

The later African Iron Age saw a shift to centralised polities, as seen in the expansion of hegemonies such as Great Zimbabwe. During this period, trade with the interior of Africa became increasingly centrally controlled. Excavations at the site of Kaitshàa, on the edge of the Makgadikgadi saltpans in Botswana, have revealed how a small settlement based on prehistoric salt trading was able to take its place in the Indian Ocean trade network before such centralised polities arose. Using compositional analysis of glass beads, the authors argue that this site in the central Kalahari Desert exemplifies the role of heterarchy and indigenous agency in the evolving political economy of the subcontinent.