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Blue gold (AuIn2 intermetallic)


Using info from research in the Gold Bulletin journals, I have been
experimenting with blue gold intermetallic alloys. Blue gold, like
purple gold, is notoriously hard to work with due to its structures,
but thru electroplating and diffusion annealing it is possible to use
in jewelry. Just an update to earlier posts I made, I have
experimented with plating blue gold. It’s a reallatively simple
process, but harder to get perfect (as of yet I haven’t perfected the
process). I just thought I would post some pictures of my trials.
These pics are of a wheat penny, the old solid copper pennies, that I
first plated in 24kt gold and subsequently in an indium sulfate
electrolyte bath. Annealing is where I’ve hit the most problems, as
the process seems to work best with the old “low and slow” method.
Temp for annealing is around 140 degC, and depending on the size of
the piece anywhere from 15-45 minutes.

Even before annealing you can start to see some blue forming.

The blue color is not a vibrant color untill light is refracted at a
certainangle, but when the light does hit the angle it’s a beautiful

From what I’ve found in my research, the finished plating can be
susceptible wearing through. Any ideas on that lacquer to use? I’d
like to find a coating that is more of a flat(satin) finish that most
of what I’ve seen to date. Also, for those with plating experience,
what do you use as a masking to prevent plating specific areas? I’ve
seen photos with a masking agent that looks like a green wax type
mask but I haven’t figured out what it is.


For masking I use finger nail polish. let it sit for 24 hours and
then plate. then a little acetone will remove the finger nail
polish. As Dara’s a protective coating the new ceramic electro
platings work quite well. Rio Grande sells it as well as a few other

Have fun and make lots of jewelry…