The metallurgy of jewelry alloys is rather unique since it has changed little since 4,000 B.C. when gold was first used for decorative purposes. One of the reasons is that the most common alloying elements for gold change its color while increasing its hardness and wear behavior. At the same time they occur in nature with gold and therefore have always been together with it in the form of alloys. At a more advanced stage of metallurgy, gold alloys were produced intentionally by refining and melting. The requirements for alloy production have been discussed elsewhere. On the other hand, the production methods did not change very much over the course of time. The highly ductile gold and gold alloys are still made into sheets, wires, shaped into bowls or disks, or even beaten into leaf about 2 micron thick. The knowledge of how to do this was still up to this day hidden more or less as a trade secret within the goldsmiths' or bullion dealers' ranks. Until a few years ago not even the composition of a jewelry alloy was published. This situation for whatever reason is reflected in the first volumes of Gold Bulletin, Volume 1, which was printed in January 1968, the first four volumes being "a quarterly bulletin of selected abstracts from the technical literature on gold!" Up to number 12, the contents did not even list "Jewelry Alloys." Among the seven "New Patents" listed, only two are concerned with gold alloy jewelry. With Volume 4, Number 1 January 1971, Gold Bulletin changed to "A quarterly review of research on gold and its application in industry" - gold jewelry being surely the biggest industrial user of gold.

Author: C.H. Raub