Provenance studies of 18th century potassium-rich archaeological glass from Portugal

Two compositional groups were identified, that besides differing in other components have different contents of arsenic oxide. None of the groups could be undoubtedly compared with the few known potassium-rich compositions from coeval glass production centres in Europe. The majority of the analysed samples could only be compared, in terms of major oxides, with the potassium-rich production from the Coina Glass Factory in Portugal.