|
Ancient Chinese glass refers to all types of glass manufactured in China prior to the Qing Dynasty (1644–1911). In Chinese history, glass played a peripheral role in the arts and crafts, when compared to ceramics and metal work.〔Braghin 2002a〕 The limited archaeological distribution and use of glass objects are evidence of the rarity of the material. Literary sources date the first manufacture of glass to the 5th century AD.〔Jenyns 1981〕 However, the earliest archaeological evidence for glass manufacture in China comes from the late Zhou Dynasty (1046 BC to 221 BC). Chinese learned to manufacture glass comparatively later than the Mesopotamians, Egyptians and Indians.〔Pinder-Wilson 1991, p 140〕 Imported glass objects first reached China during the late Spring and Autumn period – early Warring States period (early 5th century BC), in the form of polychrome ‘eye beads’.〔Braghin 2002b, p 6〕 These imports created the impetus for the production of indigenous glass beads. During the Han period (206 BC to 220 AD) the use of glass diversified. The introduction of glass casting in this period encouraged the production of moulded objects, such as bi disks and other ritual objects.〔Pinder-Wilson 1991 p140〕 The Chinese glass objects from the Warring States period and Han Dynasty vary greatly in chemical composition from the imported glass objects. The glasses from this period contain high levels of barium oxide (BaO) and lead, distinguishing them from the soda-lime-silica glasses of Western Asia and Mesopotamia.〔Kerr and Wood 2004, pp 474-477〕 At the end of the Han Dynasty (AD 220), the lead-barium glass tradition declined, with glass production only resuming during the 4th and 5th centuries AD.〔An Jiayao 2002, pp 45-46〕 ==Chemical composition of Warring States and Han period glasses== At present, it is accepted that in China, glassmaking began around the 5th century BCE during the late Spring and Autumn to early Warring States periods. Chemical analyses of glass samples dating to this time have identified no less than three glass systems: potash-lime, lead-barium, and potash; of these, lead-barium was the most significant in early China.〔Christopher F. Kim (2012), (Early Chinese Lead-Barium Glass; Its Production and Use from the Warring States to Han Periods (475 BCE-220 CE) ), PDF file〕 During the Warring States period and the Han Dynasty (5th century BC to early 3rd century AD) glass was imported from regions outside of East Asia, such as Mesopotamia. Imported Western faience and glass probably inspired the production of the first Chinese glasses. The main group of objects with Western influences are eye beads or dragonfly-eyed beads.〔Kerr and Wood 2004, p474〕 The key difference between Near Eastern eye beads and Chinese eye beads is their chemical composition. The coloured glasses used to produce the Chinese eye beads have a high lead and barium content. This type of composition was exclusive to China; and it was used to produce a range of glass objects until the end of the Han Dynasty. Table 1 shows examples of chemical compositions of some Chinese glass objects. ''Table 1: Elemental compositions of Chinese glass from the Warring States Period to Han Dynasty. Data from the first 4 objects was taken from Brill et al. 1991; data from glass garment plaque was taken from Cheng Zhuhai and Zhou Changyuan 1991; and data from the ritual disk was taken from Shi Meiguang 1991.'' The Chinese lead-barium glasses typically present 5 to 15% BaO. The source of barium in the glass in not clear; however it is possible that ancient Chinese glassmakers used witherite (a mineral form of barium carbonate) as an ingredient.〔Brill et al. 1991, p 34〕 The use of a separate ingredient implies that barium had a specific function. This function could have been to flux the glass, by lowering the melting point of the melt; or stabilize the glass, by making it less soluble to water.〔 It could also have been added to opacify the glass. Electron microprobe analysis of glass fragments have shown that the turbidity of certain lead-barium glasses is produced by barium disilicate crystals.〔〔Shi Meiguang et al. 1992, p 24〕 This turbidity gives the glasses a jade-like appearance. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ancient Chinese glass」の詳細全文を読む スポンサード リンク
|