Publication Type:Journal Article
Source:Studies in Conservation, Volume 1, p.30-38 (1952)
By taking X-ray back-reflection diagrams on an ancient electrum jewel and measuring its density, the approximate composition has been found to be: 69% gold, 28% silver and 3% copper (using only non-destructive tests). X-ray photographs on different points of the surface show that the alloy is not a single solid-solution, as required by the equilibrium diagram, but two phases: the silver-rich one is made of small crystallites, whereas the copper-rich one is much coarser. The cold-work revealed by X-rays varies from one point to another but can alsways be connected with the making of the object, thus proving that no evolution towards equilibrium has takne place in the alloy during the forty centuries of its existence.