The Production and Composition of Chinese Lead-Barium Glass through Experimental Laboratory Replication.

• Sodium is essential for lead-barium glass forming. • Previous chemical analysis of ancient lead-barium glass underestimates the sodium content. • Opaque lead-barium glass cannot be produced during the primary production. • Lead-barium glass can be produced by mixing natron glass with lead and barium minerals. Lead-barium glass appeared during the late Warring States period in China (457 - 221 BCE) and was considered as a Chinese invention due to the unique presence of high barium. There is no indication as to how it was made. A set of twenty-four different combinations of possible raw materials were melted to test and systematically evaluate the possible recipes for lead-barium glass. Specifically, the function and source of sodium in lead-barium glass were explored. The results show that sodium source is crucial for lead-barium glass forming in this particular system. This paper explores an alternative formulation since sodium flux is not reported in historical Chinese sources, in which the Na 2 O is provided by including soda-lime glass in the mixture. This particular formulation provides a potential explanation for the source of the sodium in lead-barium glass. [ABSTRACT FROM AUTHOR]