Scientific Analysis of Agate Unearthed From Liao Tomb in Zhangjiayao Forest Farm
YU Han1, 2, YANG Lu1, 2*, LI Zi-xuan1, 2, CONG Li-li3, FU Yong-ping3, SHEN Gui-yun4
1. China-Central Asia “the Belt and Road” Joint Laboratory on Human and Environment Research, Xi'an 710069, China
2. Key Laboratory of Cultural Heritage Research and Conservation, Ministry of Education, Xi'an 710061, China
3. Shenyang Institute of Cultural Relics and Archaeology, Shenyang 110033, China
4. Liaoning Provincial Museum, Shenyang 110167, China
Abstract：Agate, also known as hematite, is an important part of ancient Chinese jade. The Khitan people are particularly fond of the string decorations made of agate. Because agate accounted for a large proportion of the jade unearthed from the tombs of the Liao Dynasty, about one-third were agate, which is of great significance for studying the processing and aesthetic orientation of jade in the Liao Dynasty. However, there is little scientific and technological analysis and research on Khitan agate. Four agate beads were unearthed in Zhangjiayao Forest Farm No.1 tomb, of which No.1 bead is a necklace, and No.2—4 beads are arm ornaments. To study the characteristics and processing technology of agate unearthed in No.1 Liao Tomb in Zhangjiayao, in this paper, laser micro Raman spectroscopy, super depth of field microscopy, X-ray fluorescence spectroscopy, X-ray flaw detection and other techniques are used to observe and analyze the agate string decoration unearthed from Liao tomb in Zhangjiayao forest farm, and the source of raw materials, processing technology and preservation status are discussed. The results show that the Raman spectra of the four samples are the same, showing the scattering peaks at 130, 203, 399, 413, 462, 501, 550, 637, 688, 796, 990, 1 160 and 1 345 cm-1, the main composition of the sample is: α- Quartz and clinopyroxene, the coloration minerals are goethite, hematite and hexagonal fibrotite, and the processing technology is opposite drilling. To know the content of plagioclase in the sample, Lorentz fitting was carried out for the characteristic peaks at 462 and 501 cm-1 of the Raman spectrum of the model, and the Raman spectral band integral ratio analysis was carried out for them. The results showed that the integral ratio of the Raman spectral band of the sample was 4.18. According to the function curve, the relative content of the modelis estimated to be about 20%, calculated that the ratio of moganite and α- quartz characteristic peak areaA501/A462) is about 0.22~0.3. According to the content of moganite, it is inferred that the agate maybe North Red Agate, and the source may be the local source of LiaoDynasty. According to the X-ray flaw detection results of agate, the processing technology of tube beads is opposite drilling, and the processing tools may be solid drilling tools with a small amount of jade sand. There are a lot of soil erosion pits, crackles, whitening and other phenomena on the surface of the sample, and the overall weathering condition is relatively severe. After studying the acidity and alkalinity of the soil in the No. 1 coffin of Zhangjiayao, it is found that the soil in the wooden coffin is neutral soil, which has little impact on the tube beads. On this basis, combined with the current research on jade weathering, it is speculated that the weathering of samples is related to the quality of raw materials and the weathering of samples.
Key words：Khitan; Agate; Weathering; Producing proces
