The Corning Archaeological Reference Glasses: New Values for 'Old' Compositions

The Corning Archaeological Reference Glasses are widely used as standards in the chemical analysis of archaeological and historical glasses, as their compositions were designed to approximate those of major glass types in antiquity. Since their development in the 1960s, their compositions have been revisited and updated. This paper provides a brief overview of the Corning glasses, and addresses two of the last three elements to be re-evaluated: the recommended values for the concentrations of SO3 and Cl were, until now, based on theoretical values. Data for these elements were collected using electron microprobe, and used together with published data to suggest new values. Finally, a complete list with the most up-to-date compositions for the four Corning glasses is compiled for the benefit of other analysts.