Potash - a key raw material of glass batch for Bohemian glasses from 14th-17th centuries?

The aim of this work is to verify or refute hypothesis of existence of basic/universal glass batch: quartz sand: potash: limestone, at a ratio of 2: 1: 1 used in Bohemian glass production since the middle ages onwards and to simulate the preparation of a potassium glass type with the composition used in medieval Bohemia. The chemical composition of Bohemian glass, which incorporated in the proposed glass batch for glassmaking on a laboratory scale, was evaluated by (a) findings directly related to glassmaking (samples from glasswork in Moldava dating back to the 15th century) and (b) information from publications.Experimentally produced glasses for the present paper were prepared from raw materials such as ash, leached ash, potash, limestone and quartz sand. The plant raw materials (spruce, beech and bracken ashes, raw and refined potash) were treated and prepared by methods similar to the production procedures used in the pre-industrial era.The main contrast was found in the CaO/K₂O weight ratio, which was determined in glasses that were characteristic of given periods. While this ratio was often below 1 in glasses of the 15th century, it reached values above 1 in glasses at the turn of the 16th-17th centuries. This result may indicate that the composition of the glass batch had changed.The results of the present study reject the current scholarly work dealing with glass batch composition during the 14th-17th centuries and confirm that glass produced in some Bohemian medieval glassworks could have been melted from a batch that included plant ash, making the use of limestone unnecessary. The traditional suggestion of the exact ratios of raw materials, often cited in historical literature, seems to be impossible. The glassmakers had to react to the variable composition of the raw materials, especially plant ash.     

The coloured glass of Iulia Felix

Research on the cargo of glass in the Roman ship Iulia Felix, wrecked off the town of Grado (province of Udine, North Italy) in the first half of the 3rd century AD and composed of recycling cullet carefully selected for colour and type, provided much information on Roman glass production technology. A combined approach, involving analytical, statistical, and archaeological evidence, included chemical analyses (X-ray fluorescence, electron microprobe), which indicated that the coloured samples were all soda-lime-silica in composition, with natron as flux, although cluster analysis identified many compositional groups. Comparisons among the compositional groups of the colourless glass, previously studied, and those of coloured glass showed that the production technologies of the colourless glass vessels constitute two well-defined technological end-members, also related to group types, into which those of the coloured glass samples fall. In particular, coloured glass samples—all bottles, low-status vessels—were produced with mainly beach siliceous-feldspar-calcareous sand. However, unlike the colourless type, strict control of raw materials and decolourising processes was not adopted, and recycling was also practised, as demonstrated by the Sb₂O₃, Cu and Pb patterns. In this context, a “recycling index” (RI)—[(Sb₂O₃)_X/(Sb₂O₃)_Ref] * 100—is proposed here for the first time, in order to quantify the extent of recycling of antimony colourless glass in the batch. RI is valid for glass containing abundant Sb from an end-member of colourless glass. In conclusion, although it cannot be stated unequivocally that the identified compositional trends are related to different production centres or different raw materials, the strong evidence of compositional variability among all the Iulia Felix glass samples, both colourless and coloured, supports the dispersed production model for Roman glassware and the common practice of recycling in Roman imperial times, especially for low-status vessels.     

广西越州故城遗址玻璃珠饰的科学研究

本研究利用能量色散型X射线荧光光谱分析、共聚焦激光拉曼光谱分析、光学相干层析成像、超景深光学显微观测等多种方法对广西越州故城遗址出土的印度-太平洋玻璃珠饰进行科技分析,获取了玻璃珠的化学成分、物相结构、内部物理结构、表面显微形貌等综合物理化学信息,确定了玻璃珠的玻璃体系、制作工艺(着色工艺、成形工艺)和产地来源,探讨了以丝绸之路为主线的国内发现魏晋南北朝时期印度-太平洋玻璃珠可能的输入路线。广西越州故城遗址发现的印度-太平洋玻璃珠为中外文明交流提供了新实物证据,对深入研究我国南北朝时期中外文明交流具有十分重要的学术价值和研究意义。     

饱水平整漆膜保护方法在风篷岭汉墓出土漆器中的应用

漆器是研究古文化的实物资料,多有精美纹饰和铭文,但考古发掘出土的漆器多有饱水、糟朽和变形等病害,甚至胎体完全腐蚀,仅剩漆膜,且无法复原。在研究前人对漆膜保护的基础上,提出一种平整漆膜的保护方法,整形脱水后以棉纸为背衬、虫胶漆为粘接剂粘接漆膜,再用镶嵌磁铁的有机玻璃板夹住固定。成功保护了长沙风篷岭汉墓出土的60余件漆膜,为今后研究漆膜的保护修复方法提供参考作用。     

北京昌平沙河镇出土蜻蜓眼玻璃珠的科学分析与研究

为探讨北京昌平沙河镇墓葬出土的三枚蜻蜓眼玻璃珠的质地和来源,利用X射线衍射分析（XRD）、激光拉曼光谱分析（LRS）、便携式能量色散X射线荧光分析（PXRF）三种无损分析方法,对玻璃珠基体和眼珠分别进行了结构和化学组成的无损伤测试。结果表明,这三枚蜻蜓眼珠的基质为玻璃态物质,其化学成分表明该玻璃属于钠钙硅酸盐（Na₂OCaOSiO₂）系统;Cu和Co是主要的着色元素。考虑到三枚珠子采用的钴料成分为高铁低锰的进口钴料,同时通过与国内外相似珠子的对比,推测这三枚蜻蜓眼玻璃珠是外国进口物的可能性较高。蜻蜓眼玻璃珠所在墓葬群虽为清代,但根据初步的分析研究可推断,墓主通过收藏或其他途径获得并将其作为随葬品。     

绚丽多彩的玻璃鼻烟壶

在清代数量众多的鼻烟壶中,以玻璃为材料制作的鼻烟壶成为一颗辉煌璀璨的艺术明珠。