Compositional Characteristics of Jamestown “Tryal” Glass (Virginia, ca 1608)

Glass rinds on small Hessian crucibles from Jamestown are interpreted as samples of the experimental “tryal of glasse” known to have taken place in this early-17th-century Virginia colony Compositional analysis of the rinds indicates that, compared with the glass produced in northern Europe Waldglas ), they are strongly enriched in soda and depleted in lime This is hypothesized to result from the use of halophytic plants (sea grass?) in the Jamestown glass batches Imported decorative (beads, dress ornaments) and utilitarian (flat glass, roemer drinking glass) glass items comprise both soda-lime Venetian glass and potash-lime Waldglas , respectively The alkaline/low-Ca ternary composition of Jamestown “tryal” glass thus distinguishes it from these imported wares Environmental changes in the area (e.g., sea-level rise) since the 17th century hamper the identification of locally derived batch ingredients. For example, mass-balance calculations show that the sand used by Jamestown glassworkers was less siliceous than that presently exposed (91% SiO2) on Jamestown Island The novel composition of this “tryal” glass evidently records an adaptation of European glass batch recipes as necessitated by the scarce resources available to the glassworkers at Jamestown.