砣具配合解玉砂雕刻玉器纹饰的可能性分析

玉器是中国传统文化的标志性符号之一,但古代文献中关于玉器加工工艺的记载甚少。人们只能借助模拟实验和加工痕迹的显微分析,来解读古代玉器的制作工艺。至迟出现于商代的砣具,是一种旋转加工工具,它可显著提高玉器表面纹饰的加工效率。以往学界的主流观点是,利用砣具雕刻玉器表面纹饰(雕花)时,其锯片的硬度远低于玉石的硬度,必须添加解玉砂来辅助雕刻。然而,本文的模拟实验表明,即使不使用解玉砂,硬度低于玉石的铁锯片也能为玉器雕花;同时发现使用砣具配合解玉砂并不利于雕花操作,因此对于古代用砣具配合解玉砂来雕花的观点需要审慎解释。再者,古代也有硬度能达到或超过软玉(摩氏硬度为6-6.5)的钢,这种钢砣使用时更无需添加解玉砂。此外,显微分析表明,用现代金刚砂锯片雕花会留下独特的加工痕迹,应可作为鉴伪证据。

Feasibility Analysis of Using Rotary Incising Wheels with Abrasives to Engrave Jade

Although jade is one of the symbolic signs of Chinese traditional culture, little information is known about the carving techniques of ancient jade due to few ancient literature records or excavated tools. Research about the traditional practice of jade carving are based on modern simulation results of jade carving and tool mark analysis of carved features. Rotary incising wheels, which appeared at the latest in the Shang Dynasty, greatly improved the efficiency of carving jade. Generally, it is considered that engraving soft jade with moderate hardness (Mohs hardness 6-6.5), which is harder than the wheel materials such as bronze and iron, should use abrasives. In this paper, we suggest that an iron wheel with lower hardness than soft jade can engrave jade without using abrasives. It is not easy to use rotary incising wheels with abrasives to incise jade, and thus we should be cautious to argue that rotary incising wheels for working jade need the abrasives in ancient times. Furthermore, there existed steel with higher hardness than soft jade in ancient times, and this rotary steel wheel doesn’t require abrasives. In addition, tool marks analysis using digital microscopy showed that some special carving features existed in engraved grooves when using modern diamond saw blade, which can be evidence for identifying fake jade.