The gourd-shaped vessel: a Portuguese product?

Several glass assemblages excavated in Portugal and dated to the 17th century include a shape, derived from the traditional dried gourd bottle, that is uncommon elsewhere in Europe. Ten gourd-shaped bottles were selected from two archaeological assemblages (the monasteries of Santa Clara-a-Velha in Coimbra and Sao Joao de Tarouca) to be studied and chemically characterized by p-PIXE and LA-ICP-MS. The bright colors were analyzed by UV-Vis reflectance spectroscopy to identify the metallic ions responsible for those colors, thus revealing potential insights into color intent. Considering the complexity of the shape, some reproductions were made, indicating that the original glassmakers exercised high levels of temperature control and fully understood the Venetian technique of half-molding. Very high contents of alumina were found in the glass, which may indicate that the gourds were produced in Portugal using local raw materials.