First scientific research to trace the origins of Qin clay sealings

Clay sealing represents the key physical example of the document sealing system of the Qin dynasty in ancient China. However, only the inscriptions and aesthetic values of clay sealings have been discussed until now, and the relevant sources have not been traced from the perspective of scientific analysis. A total of 81 clay sealings unearthed in Xi’an were studied via ultra-depth field microscopy, petrographic microstructure analysis and X-ray fluorescence spectroscopy. The relevant methods of tracing and making clay samples are discussed based on the results of the literature investigation and elemental analysis. The composition, technology and spatial links between different clay sealings collected from all over the country show that highly organized sealing materials and systematic processes are important parts of the establishment of unified China. They also provide detailed and effective scientific information that is useful for the future preservation of clay sealings protection and further archaeological research.