Appendix 1: Glass Analysis

Prepared by Team Projek Dieng 2010, Jurusan Arkeologi, Fakultas Ilmu Budaya, and Universitas Gadjah Mada. Translated by Goh Geok Yian and John N. Miksic. Editors: Mahirta, Goh Geok Yian, Widya Nayati, and John N. Miksic

June 2010

Two thin shards of glass found in unit T2.2 spit 3 were sent to the FMIPA laboratory at Universitas Gadjah Mada for XRD analysis. The results of the analysis of a green shard of glass indicated composition including barium uranyl arsenate hydrate (Ba(UO²)2(AsO⁴)2 10 H²O. The blue shard indicated a composition with arsenic iodine (AlO³). Seligman and Beck (1938) stated that ancient glass was found in Henan Province from the pre-Han to Tang periods. Its main constituents were barium (BaO) and lead oxide (PbO), yielding what is known as lead barium silicate glass. This composition differs from that of West Asia, Egypt, and Rome where the main constituents were Na²O and CaO (Gan 2008).

Based on the chemical composition indicated by the XRD analysis, the glass found in unit TP2.2 spit 3 (football field sector, Dieng Plateau), specifically the green sample which contained barium, it can be determined that this glass originated from China.

The percentage of the chemical elements cannot yet be determined. This data could be obtained with SAA, but the glass would be destroyed, so that the historical evidence would be lost. Such analysis could be considered if more glass is found in the future. Based on the context of the find and its physical characteristics, it is probable that the glass in question originated from China, not Persia as was originally suspected.

The composition which includes BaO is quite significant. This is quite an early formula, having been employed since the Warring States and Eastern Han, 400 BC-AD 200. In general, the glass compositions used in China are as follows:

  1. Spring and Autumn to Early Warring States (800-400 BC): K²O-CaO-SiO², with K²O/Na²O)>1

  2. From the Warring States to Eastern Han Dynasty (400BC-AD 200), the formula used was BaO-PbO-SiO² and K²O-SiO².

  3. From the Eastern Han to the Tang (AD 200-700), the standard formula was PbO-SiO²;

  4. From the Tang to Yuan Dynasties (600-1200), the standard formula was K²O-PbO-SiO²;

  5. From the Yuan to Qing Dynasties (1200-1900) the standard formula for glass was K²O-CaO-SiO². Visual inspection of the fragments recovered indicates that they were probably parts of containers, not beads. The fabrication of blown glass containers in central and western China began in the Sui Dynasty (6th century AD). Generally the vessels made with this technique did not utilize barium oxide but contained a high concentration of lead.

Supported by an incentive grant from the School of Humanities and Social Sciences, Nanyang Technological University; by the Archaeology Unit, Nalanda-Sriwijaya Centre, Institute of Southeast Asian Studies; and by Jurusan Arkeologi, Fakultas Ilmu Budaya, and Universitas Gadjah Mada. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Institute of Southeast Asian Studies, Nanyang Technological University, School of Humanities and Social Sciences, nor Universitas Gadjah Mada.