新郑西亚斯东周玉器材料属性与加工工艺的科技分析

中国玉文化源远流长,治玉工艺经过各个时代的不断发展和完善,在一定程度上能反映古代社会生产力发展水平及文化、贸易、技术交流等信息。利用能量色散型X射线荧光光谱（EDXRF）、激光拉曼光谱（LRS）、超景深光学显微系统（OM）等分析技术,结合硅胶覆膜微痕复制技术,对河南省新郑西亚斯东周墓地出土的一批玉器进行科技分析。首先利用化学成分和物相结构分析技术确定了玉器材质的矿物属性,其次利用显微分析技术表征了玉器表面及穿孔内部和印模的加工痕迹,特别是阴刻纹饰和穿孔微痕特征,最后探讨了玉器样品的材料属性和加工工艺两者之间的联系。化学成分和物相结构分析结果表明,所分析的西亚斯东周玉器材质丰富,主要矿物组成有滑石、透闪石、水晶、云母等。玉器表面纹饰微痕特征分析表明,所分析玉器阴刻工艺采用了两种加工工具,分别是砣具和手持硬质工具。穿孔微痕分析特征表明,钻孔包括单面钻孔和双面/多面钻孔两种方式,钻孔工艺则有实心钻、管钻等。部分玉器钻孔形状和内部微痕特征表明,尽管均采用了实心钻工艺,但所采用的实心钻头在形状上存在差异,同时,也存在是否配合解玉砂进行钻孔的差异。不同材料属性的玉器采用了不同的加工工艺。滑石质玉器,莫氏硬度1,器型主要为玉片饰,其表面阴刻纹饰主要采用手持硬质工具进行刻画,钻孔主要采用了双面钻孔方式,并使用了实心钻头未添加解玉砂进行加工,钻头形状可能为圆锥状;云母质玉器,莫氏硬度2~3,器型主要为玉玦片饰,纹饰采用了砣具添加解玉砂的加工工艺,钻孔方式为单面钻孔,采用了管钻工艺。透闪石型玉器,莫氏硬度5~6,器型主要为玉片饰,表面纹饰采用砣具配合解玉砂砣刻,以双面钻孔的方式为主,钻孔工艺为实心钻头配合解玉砂工艺,钻头形状与滑石类样品一致,为圆锥状。水晶质玉器,莫氏硬度7,均为珠饰,表面无纹饰,钻孔方式为双面/多面钻孔,钻孔工艺为实心钻配合解玉砂工艺,且钻头可能为圆柱形。研究结果表明,玉器表面纹饰所采用的阴刻工艺和钻孔工艺,与玉器本身的材料属性、器型等存在密切关系。

Scientific Analysis of Materials and Technology of Jades Unearthed from Cemeteries Dated to Eastern Zhou Dynasty in Xiyasi,Xinzheng

The Chinese Jade culture has a long history. The processing techniques of jade have been continuously developed and improved during various periods, and to some extent, it can reflect the condition of productive forces, cultural, trade, technical communications and other information of ancient societies. In this paper, X-ray fluorescence spectroscopy (XRF), Laser Raman spectroscopy (LRS), Optical microscopy (OM), combined with silicone resin molding method are used to analyze some jade artifacts unearthed from cemeteries dated to Eastern Zhou Dynasty in Xiyasi, Xinzheng, Henan province. Mineral property is determined by XRF and LRS, then OM technology is used to characterize the micro-marks on surfaces, in holes of the jade artifacts, and also on the surfaces of silicone molds. Based on the features of micro-marks, the processing techniques have been identified, especially for the processing techniques of incising decorations and perforations. The relationships between mineral properties and processing techniques are discussed finally. The results of XRF and LRS show that the main mineral phases of jade artifacts include tremolite, talc, mica and crystal. According to the features of micro-marks obtained, there are two kinds of tools used to incise the decorations. One is the rotary wheels, and the other is hand-held hard tools. The micro-mark characteristics of drilling process show that solid drills and tubular drills are used to drill holes from single-side or double-sides/multi-sides. Although solid drilling technology is adopted in some jades, there are some differences in drills’ shape and abrasive sand used or not. Jades of different material properties adopt different processing techniques. Talc jade, whose mohs hardness is 1, is mainly plaques and uses pointed hand-held tools to incise surface decoration and solid tool-heads which are probably cone-shaped to drill holes without adding abrasive sand. Mica jade, whose mohs hardness is 2~3, is mainly slotted rings called Jue and uses rotary wheels to incise the surface decorations. It adopts single-side drilling method and its tools for drilling are tubular drills. Tremolite jade, which has a mohs hardness of 5~6, is also mainly plaque shaped, surface decorations are incised by rotary wheels, and the holes are mainly carried out by solid tools to drill from both sides with abrasive sand. The shape of the drills is cone-shaped, very similar to that of talc jade. For crystal beads, its mohs hardness is 7, the drilling technology mainly adopts solid tools to drill from both or multiple sides and the drills might be cylindrical. This indicates that connections between the processing technology of jade and the material properties and shape of jade do exist.