Scientists Discover Way to Turn Gold and Silver Different Colors

Coming to your store someday…red gold? Blue silver?

Scientists at the University of Southampton in the United Kingdom say they have discovered a method that can make metals appear to be different colors.

The method embosses tiny raised or indented patterns called nano-patterns onto the metal’s surface, Dr. Kevin MacDonald, program manager at the University’s Centre for Photonic Metamaterials, tells JCK.

(Photo courtesy of Optoelectronics Research Centre University of Southampton)

“This changes the way the metal absorbs and reflects light,” he says, “and therefore changes the color as we perceive it.”

He notes that for gold, the metal’s color will only show up as red or green.

“You can’t make it blue, because gold doesn’t reflect blue light in the first place,” he says.

Silver, he says, can conceivably be turned into “the entire rainbow,” and might even be able to show different colors within the same piece.

The new process doesn’t change the chemical composition of the gold, MacDonald says, just its surface.

The surface of a piece of flat gold after the application of nano-patterns, as it appears under an optical microscope. The different colored letters are created by the changes in the surface relief structure, scientists say.

This could possibly have an application for jewelry, MacDonald says, adding that his group hopes to market the technology for the industry. 

“There is a lot of work that needs to be done as far as fabrication technology,” he says. “It could be used as sort of a high-end augmentation of jewelry items.”

The work on gold was part of a much larger research project into engineering metals. The researchers have filed a patent application for their work.

Further details of the research can be seen in the International Online Journal of Optics.