Robin’s-egg blue beads (Kidd IIa40) are one of the most temporally and spatially widespread bead types. They have been found in archaeological contexts from the late 16^th- through the middle 17^th-centuries, from as far north as Ontario, Canada, to as far south as Florida (cf., Bradley 1977; Deagan 1987; Kent 1983; Kenyon and Fitzgerald 1986; Lapham 1995; Miller et al. 1983; Rumrill 1991; Sempowski 1994; Smith 1983; Wray 1983).

The seeming ubiquity of these beads has led scholars to question their collective physical similarity. A recent neutron activation analysis detected distinct differences in the chemical content of robin's-egg blue bead samples from separate time periods (Chafe et al. 1986; Hancock et al. 1994). Hancock et al. found that changes in the amounts of certain elements, particularly copper, occurred ca. 1600. Late 16^th-century beads tested higher in copper than early 17^th-century beads. Hancock et al. suggested a variety of influencing factors, including modifications in the manufacturing process, a change in the source of raw materials, emergence of new glass factories, and different bead sources and suppliers (Ibid.). Archaeologists continue to debate the reasons for the chemical transformation. Fitzgerald et al. (1995) attributed the shift in chemical signatures to differences in regional European glass-manufacturing recipes, rather than to the date of manufacture. They associated high-copper content robin's-egg blue beads with Basque traders in the Great Lakes region and those of low-copper content with traders from northern France and central Europe. Both European polities were active in the Northeast during the late 16th century.

Jamestown Rediscovery's robin's-egg blue beads vary in color. Although differential preservation factors and fluctuating soil acidity cannot be ruled out as a cause for the variability, recent chemical composition studies have indicated that copper, the primary colorant of these beads, is a highly inconsistent pigment. Depending on the composition of the base glass, it can produce hues ranging from blues to greens (Hancock et al. 1994:261). Future chemical testing can determine whether the variable hues seen in Jamestown's robin's-egg blue beads indicate their high copper content and add new insight to the discussion of why different chemical signatures exist for these beads.

Most of the robin's-egg blue beads in the Jamestown assemblage exhibited characteristics of the a speo method of heat rounding. Using a pronged iron spit that is rotated in the furnace, the a speo method often produces unique disfigurations in beads. (Karklins 1993). These imperfections include the partial fusion of multiple beads, conchoidal scars that result from a break in a partial fusion between two beads, and lopsided beads that "sag" during rounding (Ibid., 30-34). Jamestown specimens that showed evidence of a speo heat altering included two small beads that were partially fused together at their ends and several other specimens with slight unbroken glass projections likely associated with the initial stages of heat deformation (see Figure 2, top right).³