Significance of Discontinuous Precipitation of Copper in Ancient Silver

Abstract

Discontinuous precipitation of copper has been held responsible for much of the embrittlement of ancient silver objects. The detailed characteristics of this precipitation have been suggested as possible indicators of an object’s age and authenticity. These proposals are considered in the light of metallographic and analytical studies of several embrittled artifacts. These studies indicate that discontinuous precipitation is much less significant for embrittlement than residual stresses due to retained cold-work and externally applied stresses due to burial, and that the precipitation characteristics cannot be used for authentication.