Trends in Colouring Blue Glass in Central Europe in Relation to Changes in Chemical Composition of Glass from the Middle Ages to Modern Age

Zuzana Zlámalová Cílová,Michal Gelnar,Simona Randáková

doi:10.3390/min11091001

Zuzana Zlámalová Cílová, Michal Gelnar + Show 1 more

Open Access

https://doi.org/10.3390/min11091001

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Journal: Minerals	Publication Date: Sep 14, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: University of Chemistry and Technology

Abstract

The study deals with the development of the chemical composition of blue glass from the 13th to the 19th century in the region of Bohemia (Central Europe). Nearly 100 glass samples (colourless, greenish, and blue) were evaluated by an XRF method to distinguish the colouring components of blue glass. As early as in the 13th century, blue glass based on ash containing colouring ions of Co and Cu was produced here. To achieve the blue colour of glass, a copper-rich raw material was most likely applied. This information significantly complements the existing knowledge about glass colouring in the Middle Ages, as the glass of later periods was typically coloured with raw materials containing cobalt.

Highlights

The production of blue glass has enjoyed a long tradition since the Late Bronze Age and is related to areas such as Egypt or Mesopotamia [1,2]
Glass of the 12th century is that of a sodium natron type following the tradition of Roman glass production and the composition here differs from the common medieval production of potassium glass in Central and Western Europe [7]
13th century [33] and there is direct evidence of contemporary blue glass production in the form of its residual layers found on the inner surface of the crucibles (Table S1)

Summary

Introduction

The production of blue glass has enjoyed a long tradition since the Late Bronze Age and is related to areas such as Egypt or Mesopotamia [1,2]. In Europe, the occurrence of small glassware objects started to increase significantly in the 6th–5th century BC with blue beads frequently appearing in this production [3]. A large part of the finds uncovered there (more than 2000 pieces) consisted of blue glass objects. Their coloration is associated with the use of cobalt (mostly in hundreds of ppm) and copper (in thousands of ppm). Several samples show greater amounts of antimony and manganese. This corresponds well with the work [5]

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