Enameled reliquary

Method. In the present study, XRF was used to identify major elements in the enamel and the substrate of the cross and reliquary described in a previous section. We used an XRF system with a 1-Ci 241 Am source in a New England Nuclear holder. The source was used in the secondary mode with, in this case, a molybdenum target. The output of the Si-Li detector was analyzed by a Nuclear Data 6620 computer-based multichannel analyzer. The downfacing detector-source-exciter system was positioned above the objects to permit nondestructive analysis while the objects remained horizontal. 

A more detailed examination of the composition of the variously colored enameled areas was then carried out by masking all but the regions under study with double layers of 0.007-in. (0.18-mm) tin sheet of high purity. The tin by itself showed no peaks other than that of tin in the XRF spectrum, even when placed on a copper substrate. Hence the tin masks cannot have contributed to the observed peaks, nor can any of the signals detected have come from areas under the tin masks. Similar masking was performed for regions on the reliquary. 

Figure 11. XRF spectrum of the red enameled spot on the reliquary showing only the major copper peaks.

Figure 12, XRF spectrum of a light blue enameled region on the reliquary showing the major copper peaks and the Ka peak of iron.

The enamel on the reliquary, which is thinner than that on the cross, gave strong copper signals in all cases. The red spot showed only copper, and the light blue enamel contained iron the spectrum of the green enamel showed small peaks for nickel and gold. No lead was detected in any of the enameled areas on the reliquary. 

On the basis of XRF studies, the enamels of a medieval reliquary are recognizably different, a fact suggesting that the object was made in a different workshop tradition, although its the stylistic features are typical of enameled medieval objects. 

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