Between the 2nd year of the Qianfeng era and the 1st year of the Xianheng era (667-670 CE), Tang
Diameter 1.6 cm, Thickness 0.5 cm
Unearthed from the tomb of Shi Hedan and his wife in Xiaomazhuang Village, Nanjiao Township, Guyuan County, Ningxia in 1986
The Guyuan Museum of Ningxia
