Deep blue glasses coloured by octahedral Fe2+ cations are often reported as textbookexamples of blue pigmentation. However, despite the possibility of laboratory synthesis under reducing conditions, to date there are no well-reported occurrences of their production and use in the past. A thorough historical, ethnographic, mineralogical, and chemico-physical investigation of the ‘smaltini di calcara’ from several baroque churches in Palermo, Sicily, has revealed that the blue enamels widely used for altar decorations in the17th and 18th centuries are actually a unique case of ancient blue glasses pigmented by divalent iron cations in distorted octahedral coordination. This mixed-alkali glass was accidentally produced under severely reducing conditions in the local kilns during production of lime.
|Numero di pagine||17|
|Stato di pubblicazione||Published - 2009|
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