On Sat, 21 Jun 2008 14:52:20 -0700, in rec.crafts.jewelry "William Black"
<william.black@[EMAIL PROTECTED]
> wrote:
>>British Customs (I'm not sure what the agency is called this week) has
just
>>bought a very clever device for telling the origin of diamonds by some
sort
>>clever test, probably crystalography of some kind.
Very costly machines. They detect very slight differences in the various
impurities in the crystals, which tend to vary based on location. Even
then,
however, it seldom can proove origin, only suggest it, as there's
significant
overlap in these properties from one location to another. They can, for
example, take some stones and know for certain that they did not come from
Sierro leone (one of the biggest problem areas), but the machine can't
say this
for certain for all locations, especially stones from other parts of
africa with
similar geology. And then there are the stones from Sierra Leone that
happen to
be legal. Perhaps mined legally before the war, or since, etc. etc. No
separation there. And some stones, both blook diamonds and not, will
simply not
give any definative reading on the machine. It's a better test than
nothing,
but a long way from being even close to perfect. So far, the only real
solution has been requiring im****ters, cutters, dealers, to maintain a
paper
trail showing the origin of the stones. But I've yet to see a retail
store
offering retail customers any paperwork that verifiably continues this
paper
trail, so consumers are left hanging. And dishonest dealers have been
known to
forge paperwork.
>>
>>I gather that if you're even wearing too much expensive looking
jewellery
>>they get to play with it. ****pments of diamonds all get to go through
it...
****pments are probably less of a problem, since the likelyhood of proper
paperwork and do***entation is higher. Such do***entation is not likely
with
finished jewelery, and even then, the testing may be not very meaningful.
Even
if diamonds are suspected of being originally from Sierra Leone or other
conflict areas, there's no way to tell when they were mined, or if
legally. You
could have a fine diamond necklace, purchased legally in Hong Cong, with
paperwork claiming conflict free diamonds, which are in fact bloody as
hell, but
if properly declared at customs, this would be legal. no grounds to
confiscate
it. Or another similar necklace, except from Harry Winston made in 1955,
also
with stones from Seirra Leone that the machine might yell about, yet it
too is
legal and the diamonds were not in a conflict then. All in all, lots of
problems with such test. But at least, smugglers don't always know this.
The
real testers are likely to remain the customs officers themselves, looking
for
things being brought across that they can prove are illegal, or when
smugglers,
thinking themselves caught, will give away clues as to their activity.
>>I keep looking for these synthetic stones here in the UK, but, as I've
>>said before here, so far nobody seems to be interested in supplying
them to
>>jewellers in small quantities.
>>
In part, they're simply not available even in large quantities. Don't
feel
excluded. Gemesys, the main manufacturer of the nice yellow synthetics,
is not
able to make anywhere near as much as they could sell, so they hardly need
to
look for new distributors, either large or small.
>>
>>Then I must have misheard the chap at one gem supplier.
Look for Chatham ruby, or Gilson ruby, as two manufacturers of fine flux
grown
stones. The cheap stuff is flame fusion, and stones cost pennies, but are
still
ruby. Look in wikipedia for "Verneuil process", for this first of the
major
ruby synthesis processes. The result is commony used in class rings,
cheap
jewelry, industrial bearings (watch bearings are often synthetic ruby like
this). Nice bright red ruby, but easy to identify due to curved growth
marks.
Others include the "Czochralski process" (widely used for making the
silicon
crystals used in semiconductors, but also for high purity ruby, including
for
example, ruby laser rods. The result is one of those that are exceedingly
difficult to prove as being synthetic in some cases, even when common
sense
tells you it has to be so, as it's too damn perfect to be real...), or the
hydrothermal process , or Flux Growth methods. These two latter methods
often
produce gems that are Very much the same in appearance as natural gems,
with the
major differences being in the nature of the inclusions present, a
separation
that takes some training and a good microscope to do in many cases. More
than
a few gem dealers and even trained gemologists have been fooled by one or
more
of the various ruby synthetics or treatments from time to time...
Peter
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