Silk Road glass in Xinjiang,China: chemical compositional analysis and interpretation using a high-resolution portable XRF spectrometer

In this paper we explore the major, minor and some trace elements of sixty-five glass beads from eighteen oasis sites both north and south of the Taklamakan Desert, the ancient centre of the Silk Routes linking East and West; the samples date from the Warring States period (475–2211 BCE) to the Tang Dynasty (618–907 CE). Using a high-resolution portable XRF spectrometer, with special attention to issues of surface weathering and sample preparation, we obtained quantitative chemical compositional data that, when combined with archaeological context and the technology of bead manufacture, provide the basis for an understanding of both changes in glass type over time, and possible source areas for the Xinjiang glasses. While glass beads at the early sites (1st c. BCE to 4th c. CE) were coming primarily from Kushan-controlled territories in northern India, Pakistan and Afghanistan, with a small contribution from central China, most of the later glass (4th–10th c. CE) is similar to that produced in the Sasanian Empire at such sites as Veh Ardashir in central Iraq. These changes most likely reflect changing cultural and economic conditions in the Silk Road towns.