Purple gold alloy, Blue gold alloy

I came across several gold alloy formulas: Purple gold 79Au,
21Al. Blue gold 75Au, 25Fe. I have not tried them, but thought
that the formulas may help some of the Orchidians who are
experimenting with color alloys of gold. --Barbara Bequette

A few years ago I mixed up some purple gold: 79 Au + 21 Al. It
was an expensive experiment where most of the gold seemed to
vanish. However I did wind up with a little nugget encrusted with
a crinkly gold coating.

The nugget was hard as a rock. When cut open with a separating
disc the interior was composed of the most incredible color of
gold imaginable: a rich bright purple. I have since learned that
this is not a true alloy, but an “intermetalic compound,” because
the two metals do not mix. It is totally unworkable as a metal,
but can be carved with lapidary-type equipment.

Alan Revere
Revere Academy of Jewelry Arts
San Francisco

Alan, It took me twice to learn about purple gold. The first
time I simply put pure gold and aluminum in a crucible-at the
same time- and got a purple pot metal that wouldn’t ‘move’ it
just sat there and croaked! I called my great uncle Roy and he
suggested melting the pure gold first, then quickly toss in the
aluminum and QUICKLY pour it. WRONG again. The purple metal
still sat there, as if the aluminum was a catalyst for
frustration. I sent both to the refiners. I lost almost nothing
but time. But, it was a pretty color underneath the crust. It
broke like glass.