"How I do it" I facet purple gold. Purple gold? Indeed.
When pure gold is mixed with aluminum in a ratio of 79%
gold and 21% aluminum in a vacuum furnace the resultant
product is an 18ct gold that is purple in colour. (
okay, for the purists, the ratio is higher that 18ct,
since 18ct is 75%/ gold and 25% alloy, but to all
intents and purposes you can sell it as 18ct gold.)
It is, however, not
malleable, and is known as an 'inter metallic compound'
So if you want to use it in jewelry, it basically has
to be carved like a stone. And set like one. Also, you
can not solder it , nor can you roll it in your rolling
mill. It is possible to saw it with a jewelers saw, or
to file it, to give you an idea of the hardness. It can
also be sanded with your buff stick, and polished in the
normal manner that jewelry is polished. And here in
lies the rub. Because is is so brittle, it can also be
Sooo, I cut this piece of
purple gold on my Imahashi faceting machine. I dopped it as
I would a standard stone and first cut on a 260 Crystalite
lap. Then to a 1200 lap and I polished on a Batt lap with
50,000 diamond powder. The material is a bit porous, but it
gives a nice 'chrome' like polish. I am going to use this in
a pendant, since this material is unsuitable for ring wear.
So then I got to thinking
whether it would not be possible to make a composite
gemstone with real stone and purple gold. Sort of like
faceted intarsia. Thus came the following experiment.
Firstly I took some off -cuts afghan tourmaline that I had
from a previous parcel and a piece of purple gold.
And I cut and polished a face
onto the tourmaline.
And then I cut a absolutely
parallel piece of purple gold. I cut the first side and the
used my transfer block to transfer and cut the second side.
I did not polish the faces, and that appears to have been a
mistake. I thought that if I left the surfaces slightly
matt, there would be better grip when I glued them together.
However, the glue that I used was more than strong enough
and thus I lost the reflective ability of the gold. Anyway,
so this is experimental stuff and so you learn as you go
Here are the three pieces,
ready to be glued. The two tourmaline pieces are off cuts so
their colors do not match. No matter...
This is the glue I use. It is
(I'm told) used for glueing museum class cases together. It
is UV stable, immensely strong and takes FIVE DAYS to
harden. It has to measured out by weight and therefore the
gemstone scale. ( quite appropriate, I think :) It also
costs $50 for the bottles pictured and is available at http://www.hxtal.com
Here are the three pieces
aligned and being glued. I used a small 'G' clamp to hold
them together. Not much pressure, because you don't want any
distortion. I also put some masking tape onto the faces so
as not to glue the whole nightmare together. So now you wait
for 5 days.
And after five days these are
the mated pieces.
This is the piece preformed,
prior to cutting. It is now dopped in the usual manner that
gemstones are attached onto their dops and faceted in the
usual manner. This is outside the How To's scope of showing.
However, this is the stone
being transferred for cutting the crown after the pavilion
has been cut and polished. The manner that I transfer stone
is a subject of a future 'How To'... So before I get to the
final picture, a few notes on the actual cutting and
gold makes your machine dirty! It is like a dye, and gets in
composite stone was cut using 260,1200 Crystalite, 3000
copper, and 50,000 Batt
I thought that the purple gold
would give trouble with the polishing, because essentially
you are polishing stone/gold/stone on a metal lap. So
I thought that the gold would cause scratches on the
trailing edges of the stone. This did happen, but not to the
extent that I thought it would. They were more like cats
whiskers, and a change in rotational angle solved the
problem every time. Essentially I got a polish that was as
good as if the gold had not been there.
Here is a picture of the
finished stone. You can see that the two tourmaline pieces
are not of equal colour. Also on the right side there are
cracks that formed, and they did so whilst polishing
the table. That happened to be the last facet ------and is
perfectly in tune with the " First Law of Gem
Cutting", which says that the biggest fuckup always happens
on the last facet.... ........Moderate sigh...
When the mating surfaces of
the composite stone are cut with precision, the glue
component of the division is negligible, in terms of polish.
The following picture is taken
at 45 X magnification. Apart from the purple gold grain
structure the joint is very small, and under a 10X loupe is
One of the first attempts of
mine was to glue together a piece of peridot and garnet and
then facet them. From the glue aspect it was quite
successful but from the 'visual' aspect it was less so.
Namely, the garnet killed the color of the peridot. At some
angles is looks orange, because of the mix of the two colors
and at others, red.. The 'scratches' in the picture are
actually inclusions in the stone. I do not experiment with
top grade material....The next composite that I am going to
cut is going to be out of yellow and blue, which equals
green and yellow and red, making purple. Coming to a
computer near you.
This is the end of this 'How to' ---I hope you enjoyed it
comments or better ideas, feel free to send to me at