What is black gold, like in 18k?

I saw an ad in a trade magazine with the image of a black and white
bracelet. The ad said, "entirely of 18k black and 18k white gold."
Ok, does someone know what this stuff is? Is there some strange
black looking alloy or it is a treatment to provide a black color?
Any clues? Thanks and God Bless.


Black gold is a alloy whose surface turns black from oxidation. it
is available from Argen it is only a casting alloy as it is quite
brittle and must be cast in a completely controlled environment that
is totally free of oxygen. So you need one of those $50,000 casting
machines to work with it.


I believe black gold is achieved by alloying with iron. The problem
with it is that it is very hard and brittle, as well as difficult to
alloy in the first place.

Spike Cornelius
Portland, Or.
RC ArtMetal