Using Examination Methods and EDX Analysis to Study the Archaeological Vitreous Enamels

This study aims to examine and analyse different samples of vitreous enamel from two objects: one in Aljazeera Museum and the other in the Faculty of Applied Arts' Museum in Cairo, Egypt. The applied enamel decoration incorporates two sophisticated methods of enamelling: champlevé and peinture enamel, which are important techniques in enamel decoration, applied onto a metal substrate. Seven samples of different enamel colours were studied, examination was performed using a stereo and digital microscope to document the enamel surface and identify the most important deterioration aspects of enamel, which vary between pitting, cracking, separation, micro-cracks, scratches and loss of enamel........etc. The chemical composition of both types of enamel was identified using (SEM−EDX). The results proved that the enamel contains basically silicon, potassium, sodium, and lead. These enamels are classified as soda-potash glass or mixed alkaline glass. The results also proved that the colouring agents in both types of enamel are copper oxide used to produce translucent green enamel, cobalt oxide for translucent dark blue enamel, copper oxide with more sodium and potassium oxide for opaque turquoise enamel. A thin layer of gold was used under the translucent enamel to obtain the red enamel (this is an ancient technique for obtaining different shades of transparent enamel), and arsenic oxide for opaque white enamel. Moreover, the results proved that the chemical composition of enamels date back to the 19th century.