湖北随州叶家山西周曾国墓地出土玉器的玉质研究

湖北随州叶家山西周曾国墓位于湖北省随州市东北部,于2010年底被发现,出土玉石器三百余件。本文研究对象是出自M1、M3、M27、M28、M65号墓的29件出土玉器,采用宝玉石学和岩石学的研究思路和无损(微损)测试方法对该批样品进行了研究。肉眼观察结合基础宝石学测试表明,29件颜色和受沁程度不同的出土玉器样品中,27件为软玉,另2件需通过大型仪器测试鉴别。大型仪器测试以红外吸收光谱和激光拉曼光谱测试为主,对29件出土玉器样品进行玉器材质的定性分析,27件出土玉器样品显示了典型的透闪石红外吸收光谱和拉曼光谱,另2件中样品M28-63-FJ-1显示了典型的蛇纹石红外吸收光谱和拉曼光谱及样品M111∶48-50在262、405、699cm-1处显示了典型的白云母拉曼光谱。激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)对6件出土软玉样品的化学成分测试结果显示,其主要化学成分为CaO、MgO、SiO2,其质量分数分别在13.55%~14.30%,23.78%~26.02%和56.98%~58.94%之间,属于软玉的理论范围。根据微量元素中Fe的质量分数计算6件软玉样品的主要矿物种类,其中样品M65∶WH-BLACK的R*值为0.834,主要矿物组成为阳起石,其余5件样品R*值均大于0.9,为透闪石质软玉,6件样品皆产于白云石化大理岩型软玉矿床。扫描电子显微镜观察显示受沁部位的侵蚀坑以及软玉的纤维交织状结构。大型仪器可以相对准确地分析玉器的材质、化学成分和结构特征,弥补了肉眼观察和基础宝石学测试的局限性。

Jade Composition of Archaic Jade Artifact from Zeng State Tomb of the Western Zhou Dynasty in Yejiashan,Suizhou,Hubei Province

The graveyard of the Zeng State is located in the northeast part of Suizhou,Hubei Province.The graveyard was discovered in 2010,with more than 300 pieces of jade excavated.In this paper, 29 pieces of archaic jade artifacts from the Tomb M1,M3,M27,M28,M65 were comprehensively and systematically studied in terms of gemmology and petrology.The results of visual study combing with magnification observation showed that among the 29 pieces of jade samples with different colours and different degrees of soaking, 27 pieces of jade samples were nephrite, the other 2 pieces of jade samples required further testing by advanced instruments.FTIR and Raman spectrometry were used to do qualitative analysis for 29 pieces of archaic jade.27 pieces of jade samples showed the typical spectrum of tremolite in both FTIR and Raman testing, sample M28∶63-FJ-1 manifested the typical spectrum of serpentinite in both FTIR and Raman spectrum.Sample M111∶48-50 showed characteristic peaks of muscovite at 262,405,699 cm-1 in Raman spectrun.The LA-ICP-MS was used to study chemical composition for 6 pieces of nephrite archaic jade.The major chemical composition was CaO, MgO, SiO2,and contents were in the range of 13.55%-14.30%,23.78%-26.02% and 56.98%-58.94% respectively.The major mineral species of nephrite were calculated based on the content of Fe.Sample M65∶WH-BLACK with R* value of 0.834 was identified as actinolite (nephrite), while the other 5 pieces were tremolite (nephrite).Those 6 pieces of nephrite were all from dolomitization marble nephrite type.The SEM was used to characterize the jade structure.The etch pits at soaked part and the fibrous interlocking texture of nephrite could be obviously observed.The results presented that the large-scale test instruments could relative accurately give an index to the characteristic of jade texture with chemical composition and structure, which remedies the limitation of visual study and fundamental gemmological test.