Mineral soda alumina glass: occurence and meaning

Mineral soda–alumina (m-Na–Al) glass has been found across a vast area stretching from Africa to East Asia. m-Na–Al glass appears around the 5th c. B.C. and is relatively common for periods as late as the 19th c. A.D. It is particularly abundant in South Asia, where raw materials to produce m-Na–Al glass are readily available, and was likely manufactured there; however, the number and the importance of the manufacturing centers is unknown as archaeological information are extremely scarce. The interpretation of data obtained using compositional analysis on a large corpus of artifacts (486) shows that at least five sub-groups of m-Na–Al glass can be identified using the concentrations of calcium, magnesium, uranium, barium, strontium, zirconium and cesium measured with laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS). From this data, it is possible to infer the existence of several m-Na-Al glass making centers, not all of them located in South Asia as previously assumed. They were operating over different time periods and were connected to different exchange networks.