European White Glass Trade Beads as Chronological and Trade Markers
- PDF / 617,665 Bytes
- 11 Pages / 398.7 x 622.26 pts Page_size
- 81 Downloads / 211 Views
181 Mat. Res. Soc. Symp. Proc. Vol. 4620 1997 Materials Research Society
extended or drawn into tubes and then segmented, are mostly of a soda-lime glass composition. "Wound" beads, fashioned by wrapping viscous glass around a wire, are usually made of potash glass. Lead glass beads are either "drawn" or "wire-wound". The second major study [8] established that 16th and 17th century European blue glass trade beads from aboriginal sites in the eastern Great Lakes area of North America could be analyzed non-destructively using low neutron dose instrumental neutron activation analysis, so that the beads could be returned to their keepers. They found that dark blue (Co-coloured) beads are readily separable from turquoise (Cu-coloured) beads. They also found that differences in the chemistries of the turquoise blue beads appeared to be useful in separating glass beads made in the 16th century from those made in the early 17th century. The third study [9] investigated turquoise blue glass trade beads from well dated late 17th to early 20th century sites and collections, also using instrumental neutron activation analysis. The beads were found to display enough variations in their elemental contents to allow a chronological separation of the different chemical groups. The implication of these results was that similar chemical analyses of turquoise blue beads from undated archaeological sites may be used to help date the sites, since each bead chemistry has a specific earliest date. It is now of significant archaeological interest to determine whether white glass beads follow similar chemical trends over time to those of their blue cousins. It is also important to establish whether or not beads of a specific shape were made from the same glass formula. If a chronological change in chemistry can be established, we will have a new form of archaeometric evidence with which to help in the dating of post-European contact, archaeological sites. This study aims, using chemical analysis of white glass beads from relatively well dated 17th, 18th and 19th century archaeological sites, to begin the establishment of the time periods during which the opacifying elements Sn, Sb and As were used sequentially in plain white glass trade beads. If this aim can be realized, and it may need more beads from more sites than were available for this present study, then it may be possible to address the issue of chronological changes in bead chemistry within the different series of Sn-, Sb- and As-rich white glass trade beads. This, in turn, might parallel chemical changes that have been established recently for turquoise blue glass beads from the eastern Great Lakes area of North America [8,9] and appear to be translatable to turquoise blue glass beads from Qudbec [10]. Sites and Samples This paper addresses the white trade bead differentiation problem using the nondestructive chemical analysis of beads from thirteen archaeological sites of different ages (see Table 1), together with some additional more recent beads. Seventeenth century sites
Data Loading...
