Chemical Composition: 1978.495.37
Fibula
XRF data from Tracer
Alloy: Gilt Brass
Alloying Elements: copper, tin, zinc
Other Elements: lead, iron, silver, gold, mercury
Comments: Gold and mercury are present due to amalgam gilding; the black strip along the bow is very similar to the base metal.
K. Eremin, January 2014
XKA 142
XRF data from Tracer
Alloy: Leaded Copper with traces of gilding
Alloying Elements: copper, lead
Other Elements: iron, gold, mercury
Comments: The object is amorphous and extremely corroded; it may be slag. Traces of gilding may be the result of long-term contact with 1978.495.37.
K. Eremin, January 2014
Technical Observations: The surface preserves the remains of gold leaf over a reddish-brown substrate, and there is some green corrosion over both. One terminal knob from the crossbar, the pin, and the small interior rod that would have secured it are missing.
The elaborately fabricated fibula was made from three hollow sections of hammered sheet: the crossbar, which had flanged ends to receive the hollow knobs; the bow; and the catchplate. The decorative reinforcements in the corners where the bow joins the crossbar and the decorative attachments on the catchplate are solid and were probably cast by the lost-wax process. A gilt beaded wire was used to reinforce and conceal the joins of the knobs at the ends of the crossbar and top of the bow. Another gilt beaded wire and seven pieces of gilt straight wire decorate the lower end of the bow section. All the various parts of the fibula appear to have been joined by soldering. The surfaces were covered with gold leaf before the wires were soldered on. Excess gold leaf can be seen under magnification where the central knob joins the bow. The outer curve of the bow and the outer flat surface of the catchplate have a black inlay material that x-ray fluorescence indicates contains mostly copper with little or no silver. This suggests that the material could be a copper sulfide niello (1).
NOTES:
1. See W. A. Oddy, M. Bimson, and S. La Niece, “The Composition of Niello Decoration on Gold, Silver and Bronze in the Antique and Medieval Periods,” Studies in Conservation 28 (1983) 29-35, esp. 31.
Carol Snow (submitted 2002)