Natron glass beads reveal proto-Silk Road between the Mediterranean and China in the 1st millennium BCE

Abstract

Natron-based glass was a vital part of material culture in the Mediterranean and Europe for nearly two millennia, but natron glass found elsewhere on the Eurasian Continent has not received adequate discussion, despite its influence on ancient Asian glass. Here we present a new interpretation of natron glass finds from both the West and the East. After establishing the compositional types and technological sequence of Mediterranean natron glass (eighth-second century BCE) using trace elements, we report the analysis of a mid-1st millennium BCE glass bead from Xinjiang, China, which was likely made with Levantine raw glass, and identify common types of stratified eye beads in Eurasia based on a compositional and typological comparison. Combining these findings, we propose that a considerable number of Mediterranean natron glass products had arrived in East Asia at least by the fifth century BCE, which may have been a contributing factor in the development of native Chinese glass-making. The swift diffusion of natron glass across Eurasia in the 1st millennium BCE was likely facilitated by a three-stage process involving maritime and overland networks and multiple forms of trade and exchange, indicating a highly adaptable and increasingly efficient transcontinental connection along the ‘Proto-Silk Road’.

Early Islamic glass (7th– 10th centuries AD) in Unguja Ukuu, Zanzibar: A microcosm of a globalised industry in the early ‘Abbasid period

“…3 ppm) ( Fig 5 ), which suggests quartz sands, which are rich in calcium carbonate and heavy accessory minerals like titanite, rutile and zircon, were likely used to make these glasses. The low concentrations of Sr (143 ppm– 155ppm) in the glass indicate the presence of limestone in the sands [ 37 , 40 ]. UU Natron Type 1 also has a relatively low concentration of Ba (146 ppm– 149 ppm) and may partly have derived from limestones in sands [ 40 ].…”

“…The low concentrations of Sr (143 ppm– 155ppm) in the glass indicate the presence of limestone in the sands [ 37 , 40 ]. UU Natron Type 1 also has a relatively low concentration of Ba (146 ppm– 149 ppm) and may partly have derived from limestones in sands [ 40 ]. The higher levels of REE such as Th (1.17 ppm– 1.20 ppm) and light REE such as La (5 ppm– 6 ppm), suggest they were introduced to the glass with heavy minerals like monazite [ 41 ].…”

“…Th and La are often associated with heavy minerals such as monazite and allanite. The high and positively correlated Th and La ( Fig 6 ) suggests they were likely introduced with heavy minerals such as monazite and allanite [ 40 ].…”

“…(143 ppm-155ppm) in the glass indicate the presence of limestone in the sands [37,40]. UU Natron Type 1 also has a relatively low concentration of Ba (146 ppm-149 ppm) and may partly have derived from limestones in sands [40].…”

Connected in diversity: Isotopic analysis refines provenance for Islamic plant-ash glass from the eastern Silk Roads

“…One of the most widely used synthetic materials in history, glass was extensively traded along the Silk Roads, a transcontinental network of communications (e.g. 1 , 2 , 3 , 4 ). In particular, Islamic plant-ash glass (circa 9 th –15 th century) offers insights into the trade and technological evolution along the medieval Silk Roads (e.g.…”