Composition and Origin of Early Mediaeval Opaque Red Enamel from Britain and Ireland

Abstract

Opaque red enamel was examined semi-quantitatively using X-ray fluorescence on 41 objects dating to the Early Mediaeval period, and 11 of these were analysed quantitatively using energy-dispersive X-ray analysis in the scanning electron microscope. The enamels are copper-lead-silica glasses, and differ from the opaque reds of the pre-Roman and Roman periods in their low alkali contents. The red glass ingot purported to be from near Kilmessan and the Hill of Tara, Ireland, and previously thought to be a potential source for much Early Mediaeval Celtic enamelwork, is of the earlier type and is thus not related to Mediaeval enamelling. The compositional difference is paralleled in a small number of lead isotope analyses. It is demonstrated that the enamels most probably represent re-use of metallurgical raffination slags.