[Spectral analysis of pottery-painting pigments from the Monarch Bai Tomb of Zhongli State].

Based on the analysis of Raman spectroscopy and XRD methods, the structures of different pigments on the painted pottery from the Monarch Bai Tomb of Zhongli State in the middle and late Spring and Autumn period at Shungdun Village, Bengbu City, Anhui Province were analyzed. The result shows that all the pigments, including red, yellow and black pigments, have been well preserved, and these three pigments were identified as cinnabar, goethite and carbon black respectively. Both Raman spectroscopy and XRD analysis show that the crystal composition of red pigments, cinnabar, is very pure without quartz crystal, the associated crystal of natural cinnabar, and at the same time the crystal size of cinnabar is possibly at the nanometer scale. It suggests that this red pigments perhaps were a synthetic material or processed and purified by our ancestors. The discovery of goethite shows that this mineral has been used as pigments as early as in the Spring and Autumn period. This is the earliest example that goethite was used as yellow pigments.