Gerry and All,
I have never seen a natural amethyst of sufficient size (about 1+
carats) that does not have tell-tale color zoning. It can be hard to
see, may require immersion, magnification, good lighting, & proper
color background - but it is always there from what I have seen.
Small stones may be impossible to to identify due to their size in
relation to the size of the color zoning.
IMO the frequently fluctuating natural environment causes the
numerous tell-tale color zones in the natural material. By contrast,
synthetic amethyst is grown fairly rapidly in a fairly constant
environment (big pressure cooker) which does not create the
conditions that cause the color zoning seen in the natural
counterpart. This will always be the case since nobody wants to
induce expense increasing solution, radiation, etcetera fluctuations
& wait around for 10 years or 100 years before pulling their
synthetics out of the auto-clave (pressure-cooker). That is what
Mother Nature does.
Besides this, if you have samples of the synthetic materials you can
see some of their tell-tale color zoning which is different in
character than the natural. The real problem in identifying natural
from synthetic amethyst lies in amethyst’s relatively low price. If
the effort costs more than the stone, even if the stone is natural,
it becomes… “uneconomical” .
Since amethyst specimens and crystals were my specialty (along with
cut stones) back in the old days - I took great interest in the
synthetics when they first appeared. The fact that Guerrero
amethyst was and still is the finest natural material IMO ever to be
mined, caused me great concern and reason to study the “new”
synthetics. The fine color synthetics definitely kicked the fine
natural stone market in the butt!
(Some of you may remember me from all the awesome Veracruz and
Guerrero amethyst specimens & crystals in Rm # 212 at the Tucson
Desert Inn. )
Regards, Steve Green - Rough and Ready Gems, Inc.
PS I will be traveling and out of touch for a few weeks. Also I
have had a hard time posting here lately. Three of them have not
appeared yet and it has been 3 days now.
In my experience, the quickest way to spot synthetic quartz
is to check for black light fluorescence.
Upon reading this I checked my entire amethyst inventory, including
several known man-made cut stones as well as Russian hydrothermal
rough. Result: no fluorescence in either natural or synthetic. I
checked carefully under both long and short-wave. I was disappointed
because I’d hoped this might be a simple solution to an irritating
problem.
I don’t dispute that there may be fluorescent synthetic quartzes.
Colored varieties of hyro quartz have been around since approximately
1970. Many companies around the world have grown them for gems,
using additives to achieve the desired colors before color centers
were well understood. It’s very possible some additives cause
fluorescence. My little test demonstated that the lack of
fluorescence does not prove natural origin for amethyst. Neither does
the presence of twinning.
Learning to recognize natural inclusions and especially color zoning
in amethyst (as Steve Green has explained in detail) may be the best
way at present for jewelers to distinguish between the two. Some time
back I recall reading that the AGTA gem lab had a reduced-cost
program to screen parcels for large amethyst users. I think the GIA
may have a similar program. I don’t recall the tests they use but
they’re more sophisticated than those available to small gem labs.
Rick Martin
MARTIN DESIGNS
Further test for separating natural amethyst from synthetic quartz
is by using infra-red spectroscopy. The result clearly show the
difference, although sometime it can be slightly difficult depending
on the interpretion of the spectrum. Expensive technique but
reliable.
Cheers,
Tay
But just like with the very BEST MAN-MADE diamonds the UV
light will show the true from the MAN-MADE.
Dear William,
From what I know, I have to disagree with the above statement you
made. I do not think that fluorescence alone will allow you to
distinguish either synthetic diamonds or synthetic amethyst from
their natural counterparts. I have heard and seen demonstrated that
synthetic diamonds are slightly magnetic and with a powerful enough
rare earth magnet along with proper low friction placement (on a
cork on water or suspended from a string) this magnetic attraction
can be demonstrated.
(Anyone care to comment on the above? I am not sure if it proven
that all synthetic diamonds are magnetic.)
As for amethyst, I have already stated my case in past posts on the
need to visually recognize natural growth clues within the stone.
Regards, Steve Green Rough and Ready Gems - your briolette source
PS Very soon we will have pre-fitted specialty ‘pin-caps’ to fit
our briolettes in 14 & 18 K yellow or white gold. These will
increase setting strengths, decrease manufacturing time and
dramatically lower your costs.
I have heard and seen demonstrated that synthetic diamonds
are slightly magnetic and with a powerful enough rare earth magnet
along with proper low friction placement (on a cork on water or
suspended from a string) this magnetic attraction can be
demonstrated. (Anyone care to comment on the above? I am not sure
if it proven that all synthetic diamonds are magnetic.)
That all synthetic diamonds are or were magnetic would be impossible
to prove. As I understand, no natural diamonds have proven magnetic.
Thus, one can only conclude that when one encounters a magnetic
diamond, one is safe to assume that it is synthetic.
That all synthetic diamonds are or were magnetic would be
impossible to prove. As I understand, no natural diamonds have
proven magnetic. Thus, one can only conclude that when one
encounters a magnetic diamond, one is safe to assume that it is
synthetic.
The synthetic diamond itself isn’t magnetic either. But they’re a
sort of flux grown product, and the flux material is magnetic, so if
the diamond has any inclusions of the flux, which is almost
impossible to completely prevent, so I understand, then it will
provide a small bit of magnetic material within the stone.
Peter