It is possible to have a gold ring electroplated with platinum. In this process, the gold ring is dipped into a solution containing a dissolved ion of platinum. An electrical current is applied, causing the platinum ion to attach to the gold ring in a very thin coating.
Typical depths of these coatings vary from 0.5 to 5 microns. Platinum electroplating is applied to jewelry to improve appearance and durability, since platinum has a purer luster than gold and does not tarnish or oxidize. A gold ring that has been electroplated with platinum varies in color from tin white to matte gray depending on the original finish of the gold ring, the precise activation process, and thickness of the platinum coating applied.