These are not scientific
experiments. Nor scientific desertatations. This is just me
messing around in my workshop, practicing medieval alchemy.
In modern times.
I first read about purple gold in a magazine called Aurum
in 1984. I only acquired som in 1998 from a company call
Mintek, in South Africa. I gave them my fine gold and they
made me some buttons of material. They still make and sell
My experiences in working purple
Firstly, PG is not malleable. It cannot be mechanically
deformed, bent or stretched in any way in the manner that
'normal' gold can. When the gold is made it contains an
alloy of more or less 75-80% fine gold and 20-25% aluminum.
These are melted under an inert atmosphere, or in a vacuum
oven. The result is known as an 'inter metallic compound".
In the paper of the world gold council found at:
they say that PG tarnishes easily. I have found this
to be untrue. It does tarnish, but only as fast as 18kt.
yellow gold. Basically, if you work in PG you
will treat is as a gemstone. All my jewellery that I have
made, I have treated the material as such. See:
Faceted Purple Gold
However, recently I purchased a
dental vacuum oven
This oven is circa 1980, analogue and in perfect condition.
It has got a separate vacuum pump. The first thing that I
did after cleaning, drooling, and installing it was to see
what happens when you put gold and Aluminum in it. Thusly:
This was gold in the correct 18kt proportions.
I just used two soldering pads that I cut to size and then
ground some concave depressions in. Then I put a little
brazing flux in. I told you this is alchemy!
I put them on top of each other, so forming a little hollow
in them. Then I put them in the oven at 1150º Celsius under
vacuum and when the reached the temperature, I held it there
for 4 minutes. This is an arbitrary time, but it seems about
This is what it looks like when it comes out. Notice that is
is not melted in a nice sphere as normal metal would.
Remember that this might not be the case with sophisticated
equipment in a fancy laboratory. I have a standard jewellery
workshop with a bent to alchemy :) I am going to try get
some high temperature ceramic to melt in. The solder pad
absorbs all of the flux. (which might or might not be a good
thing, I don't know)
this is what it look when it cools down. All wrinkly and
After I pried it out, I rough filed it and this is what it
This is what it looked like after a crude polish. It is
actually a better colour that the picture shows. The stuff
is difficult too photograph on the fly....
I also made a mixture of 90% gold and 10% aluminum and Lo
and Behold! No purple colour. Most amazing. I am going to,
in future experiments, play around with various mixture
percentages and materials. Also to see if I can solder the
stuff under vacuum.But its expensive. I can't lock up too
much of my gold in experiments.
microscope picture, showing amazing little tri-angular
crystals. This picture was taken through the microscope lens
with my camera so the quality is not too great.
So this piece had a big hole
in it and was to pourous. I think it might have something to
do with how long I keep the maximum temperature, or maybe
the temperature is to high, or both. More experimenting is
called for! Anyway, so I decided to re-heat this piece up
and see if it would 'slump' and maybe become less porous.
No cigar, I'm afraid. All it
did was ooze some aluminum little bubbles. It is still
purple inside though...So, at this stage, is seems that once
the stuff is fused I can not re-melt it.
Weird. I imagine with an Argon atmosphere it
would melt...maybe. Okay so this is as far as I got. I'll
add more as I go along.
Hans Meevis 12/10/2007
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