Lasers Make Other Metals Look Like Gold - New York Times

This new process could have some very interesting applications in ethical jewelry sourcing (for instance, when used instead of plating, which can be a dirty process):

"In a feat of optical alchemy, Dr. Guo, a professor of optics at the University of Rochester, and Anatoliy Y. Vorobyev, a postdoctoral researcher, use ultrashort laser bursts to pockmark the surface of a metal in a way that is not perceptible to the touch — it still feels smooth to the finger — but that alters how the metal absorbs and reflects light.

The result is that pure aluminum looks like gold, and the appearance is literally skin deep.
'I cannot tell it’s not gold,' Dr. Guo said. 'It looks very pretty.'"

Check out the full article:
Lasers Make Other Metals Look Like Gold - New York Times