Neutron Activation Analysis of Sixteenth‐ and Seventeenth‐century European Blue Glass Trade Beads From the Eastern Great Lakes Area of North America*

Sixteenth‐ and seventeenth‐century European blue glass trade beads from aboriginal sites in the eastern Great Lakes area of North America have been analysed non‐destructively using low neutron dose instrumental neutron activation analysis, so that the beads could be returned to their keepers. Dark blue (cobalt‐coloured) beads are readily separable from turquoise (copper‐coloured) beads. Differences in the chemistries of the turquoise blue beads appear to be useful in separating glass beads from the two centuries. Low calcium, sixteenth‐century turquoise beads tend to distintegrate by a leaching of the alkali metals.