Did ancient glassware travel the Silk Road? X-ray fluorescence analysis of a Sasanian glass vessel from Okinoshima Island, Japan

The use of a portable X-ray fluorescence spectrometer revealed the provenance of a shard of a relief-cut glass bowl which was dedicated to ancient ritual on the sacred island of Okinoshima, Japan over a thousand years ago. The shard was unearthed from one of the ritual sites on the island in the 1950s and is now designated as a national treasure in Japan. A nondestructive and on-site X-ray fluorescence analytical technique was applied to the Okinoshima glass shard to establish where and when it was originally manufactured based on its chemical composition. Clear correspondence of chemical composition between the shard and glass excavated from a Sasanian city site in Mesopotamia demonstrated that the shard was derived from a type of glassware primarily produced in glass workshops within the Sasanian Empire between the fifth and seventh centuries AD. This is the first scientific evidence demonstrating that glass was imported from overseas across thousands of kilometers and then dedicated for the ritual on Okinoshima Island. This simultaneously gives us a glimpse of the specific details of divine rituals conducted on Okinoshima Island in ancient times.