One of the critical issues of the Muranese glassmaking technology is the induction of potassium nitrate towards the end of the 17th century. The close examination of a number of 19th century Muranese glass recipe books suggests that the use of potassium nitrate, together with lead compounds additions resulted in a change in composition of the glass used for beads, enamels and blown objects from the traditional soda-lime crystal glass to a potassium-lead glass produced throughout the 18th to the first half of the 19th century. Recently uncovered documents concerning the purchase of raw materials, instead, point to a prevailing use of soda ash, at least for less valuable glass types. The recipe book examined, particularly the Barbinis', attest to a continuity in the glassmaking technology as concerns the raw materials used. On the other hand, new types of glass were re-discovered after the crisis occurred at the beginning of the 19th century, such as aventurina, twisted filigree, chalcedony glass, gold-leaf mosaic glass. Some relevant original recipes by Pietro Bigaglia and Lorenzo Radi are discussed. Beside the advent of new raw materials (sand, colorants, opacifers) in the second half of the 19th century, the introduction of calcium compounds and industrial soda lead to a return to the traditional soda-lime composition for blown glass used up to present time, whereas the potassium-lead glass was being used for beads and enamels at least up to the end of the century.
