Chemical Composition: Mirror
XRF data from Artax 1
Alloy: High Tin Bronze
Alloying Elements: copper, tin, lead
Other Elements: iron, arsenic?
Comments: It is not possible to tell whether this is tinned or a high tin bronze without sampling.
Back of mirror
XRF data from Artax 1 and Tracer
Alloy: Mixed Copper Alloy
Alloying Elements: copper, tin, lead
Other Elements: zinc, iron
K. Eremin, January 2014
Technical Observations: A shiny, mirrored surface is preserved on approximately one-tenth of the obverse; the rest of this surface is covered with raised green corrosion products. The back is covered mostly with a thin, dark patina and some raised green corrosion products.
Hundreds of marks that appear to be hammer marks from a forming process are visible on the reverse. However, small raised features on this side appear to be casting artifacts and are incompatible with a hammered surface. It is likely that the disc was formed by casting. The mirror side is slightly convex, and the edge is slightly irregular rather than a perfect, smooth curve. The preserved portions of the shiny surface are completely white (colorless); according to XRF analysis, this portion is a high-tin bronze. There is no evidence of a hinge or any other attachment on either side, although such evidence may be hidden under the thick layers of corrosion on most of the mirror side.
Henry Lie (submitteed 2011)