The karat-gold jewelry alloys are well known for their range of unique colors―from red, pink, yellow, pale yellow to green and white―which can be obtained simply by varying the amount and ratios of the alloying metals. More unusually, it is also possible to produce karat-gold jewelry in special colors such as blue, black, brown and purple. Gold jewelry with such color effects is commercially available and becoming increasingly popular. It is also possible to have unusual colors in the other precious metals used for jewelry, but these have received little attention to date.

The focus of my 2004 Santa Fe Symposium® presentation was on gold colors, but this present update includes all other jewelry precious metals and more recently published work, particularly in how such colors may be used practically to make attractive colored jewelry. In reviewing this topic, attention is also given to other potential approaches to broaden the range of colors for jewelry that are emerging in the literature, including nanotechnology and laser ablation of the surface.

Author:  Dr. Christopher W. Corti