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To be purple or not to be purple? How different production parameters influence colour and redox in manganese containing glass

Journal Contribution - Journal Article

The purpose of this paper is to understand why manganese containing Roman glass could be purple or colourless in spite of having very similar chemical compositions. The strategy followed to tackle this question consists in the production of glass with the same chemical composition as Roman glass whereby various production parameters were controlled and systematically analysed. It is shown that redox and colour of glass is more likely to have been managed through internal control through the choice of raw materials and the addition of organic matter. The main difference between ancient and modern glass production relies on the lower melting temperature of Roman furnaces, so that sulphate would have played a less important role in the redox determination.

Journal: Journal of Archaeological Science: Reports
ISSN: 2352-409X
Volume: 27
Publication year:2019
Keywords:Colour, Glass production, Iron redox ratio, Manganese, Optical spectroscopy, Roman glass