Does anybody knows how to make black gold.(Rothelium)
There is a 14ct alloy that is made up of 1 part gold and 0.713
part = iron. It is apparently quite brittle and almost impossible
to work. As = iron is one of the components, I would expect that
an inert gas = atmosphere is necessary during melting. Hope this
helps a bit.
If you are looking for a metal that has a truly black color you
might want to try heat oxidizing niobium. The pent-oxide of
niobium is a very dark charcoal color and can be burnished to a
nice luster.If you matt finish the niobium before heating it, the
finish is a soft light absorbing black.
The iron based gold alloys that I have seen are lighter in color
and bluish- similar to tantalum.