Nephrite origins of ancient jade artifacts from the Houtaomuga site in Northeast China

Located in the core region of prehistoric cultures in Northeast China, the Houtaomuga site preserves important Neolithic jade artifacts, yet their material composition and provenance remain unclear. In this study, six intact jade artifacts and three fragments were analysed through macroscopic observation, physical testing, Fourier-transform infrared (FTIR) spectroscopy and Raman spectroscopy. All samples are identified as tremolite nephrite, providing the mineralogical basis for provenance assessment. Nonetheless, two distinct groups emerge: white to greenish-white, transparent to semi-transparent intact artifacts, and grey-yellowish green, translucent fragments. The intact artifacts retain naturally weathered surfaces, indicating that their sizes and shapes were constrained by the original raw stones. Comparison with published reference data shows that the white nephrite does not match known sources in Xiuyan, Chuncheon or the Baikal region, whereas the grey-yellowish green fragments likely derive from Xiuyan. These results clarify the raw-material diversity of the Houtaomuga assemblage and outline a dual pattern of jade supply in Neolithic Northeast Asia.