The composition of colourless glass: a review

A total of 1496 investigated colourless glass analyses have been collected with the aim of achieving a clear geographical, typological, chronological and compositional overview on this particular type of glass. Based on manganese and antimony contents, four main groups were characterised: naturally colourless, Mn-decoloured, Sb-decoloured and Mn/Sb-decoloured. Main achievements relates to the chronological distribution of manganese and antimony technologies, the former being associated to a long lasting technology which culminated during the Late Antique period while the latter being practically absent after the 8^th century AD, being at its acme during the Roman imperial period. Except for naturally colourless glass, glass-making technology mostly implied the use of impure sands and natron, relegating the other components to a virtually irrelevant ?presence?, except during the  Late Antique and Medieval periods.