Scientists 'Change The Colour' Of Gold

[S.Shorland]

http://uk.news.yahoo.com/experts-cha...230406521.html

[Steven Douglas]

http://uk.news.yahoo.com/experts-cha...230406521.html

Interesting - without changing the elemental properties, but only the surface texture, and how it absorbs and reflects different wavelengths of light. And not just gold, but all metals. That could have big implications for anti-counterfeiting measures on hard specie--even all coinage and bullion--in the future.

+rep good find!

[Meatwasp]

Our gold that we mined would turn a pretty greenish color. We found that tiny bits of platinum will do this.

[Carson]

Interesting - without changing the elemental properties, but only the surface texture, and how it absorbs and reflects different wavelengths of light. And not just gold, but all metals. That could have big implications for anti-counterfeiting measures on hard specie--even all coinage and bullion--in the future.

+rep good find!

That's pretty cool.

"This is the fundamental principle we have exploited in this project. By embossing metals with patterns only around 100 nanometres across, we've found that we can control which wavelengths of light the metal absorbs and which it reflects."

Sometimes when you machine metal you can get a rainbow effect. It seems to be a combination of the finish and the lighting. It could also have something to do with the oil. I've also seen the effect in cut meat at the deli counter.

Like Meatwasp mentioned there is also a way to change the color with alloys. Black Hills Gold is famous for it.



I think the red gold is from copper and the green it from the nickle added (Oops! I was sadly mistaken).

As for this being use to control the counterfeiting I don't hold out much hope. The worst counterfeiters we have are the ones that see no problem with it unless they have a little competition.

All in all though this sounds like a great breakthrough.