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Amethyst identification?


#1

With the large amount of synthetic amethyst out there has anyone
found a good way to tell natural from man-made? Ron
www.kreml.com


#2

Ken Scarrett at the Asian Institute of Gemology Labs supposedly
has a cost effective way to tell but I haven’t seen or read about
the methodology yet…

Marty Haske

Adamas Advantage Software: for Gemology, Mineralogy, Inventory

SAS2000 Spectrophotometer Analysis System For Diamond Color Grading,
Diamond Synthetic And Treatment Detection, And General Gemstone ID
Software Demos And Grading Issues at
http://www.gis.net/~adamas/
Email Martin Haske :@Martin_Haske


#3

With the large amount of synthetic amethyst out there has anyone
found a good way to tell natural from man-made? Ron
www.kreml.com

Ron,

Short of sending it to a lab, if you have a loupe or microscope,
check for inclusions. If you have a very dark stone with no
inclusions, I would be inclined to assume that it is synthetic,
particularly in larger sizes. The “Japanese” amethyst, as my
supplier calls them, are actually a reconstituted stone, using
actual amethyst crystal which is regrown under ideal lab
conditions, producing a beautiful, inclusion free stone. Most
natural quartz will show some inclusions. Unfortuneately, since
the cost of amethyst is so low, it is not worth the cost of lab
analysis in most cases. Even if you are buying quantity, you may
have both natural and synthetic mixed together, so spot checking
may not even tell you if a batch is all natural.

Your only defense is to find suppliers whom you really can trust
to know their suppliers. I have found The Kay El Co. in Dallas
TX to be very honest.

Perhaps someone else can add a more precise means of
identification.

Hope this helps.

Sharon


#4

Thanks for your response. I met Kay El at the jewelry show in
Dallas and have had no business with them as yet but will try. I
can just imagine the legal problems with selling what might be
man made for natural. Hope someone else could elaborate on
identification. Ron www.kreml.com


#5

hi ron,

i’m relying on dim and dusky memory here so i may not be
accurate. as i remember synthetic amethyst has twinned
parrellell growth lines. the xtal grows for a while, then
reverses growth. this is evident in all synthetic amethyst and
only extremely rarely in nature. the parrellell twinning is
apparent when viewed in a polariscope. i really don’t remember
if the polarising filters would be ‘crossed’ or ‘aligned’ or if
the amethyst should be immersed in water or methylene iodide.
hope this helps somewhat.

best regards,

geo fox


#6

hi ron,

        i'm relying on dim and dusky memory here so i may not
be accurate. *as i remember*  synthetic amethyst has twinned
parrellell growth lines. the xtal grows for a while, then
reverses growth. this is evident in all synthetic amethyst and
only extremely rarely in nature. the parrellell twinning is
apparent when viewed in a polariscope. i really don't remember
if the polarising filters would be 'crossed' or 'aligned' or if
the amethyst should be immersed in water or methylene iodide.
hope this helps somewhat. 

Synthetic quartz is now grown using natural twinned "seed"
crystals resulting in twinned synthetics, according to the
literature…no longer a reliable test, I believe

Marty Haske.

Adamas Advantage Software: for Gemology, Mineralogy, Inventory
SAS2000 Spectrophotometer Analysis System For Diamond Color Grading,
Diamond Synthetic And Treatment Detection, And General Gemstone ID
Software Demos And Grading Issues at http://www.gis.net/~adamas/
Email Martin Haske mailto:@Martin_Haske for more


#7

Sharon your right about some inclusions however it is not proof
positive. When I was a student at GIA we learned to differnciate
by the test I refer to as the magic wand test, bulls-eye figure
however, from what I have gathered that is no longer proof
positive they are always creating a better way to deceive. Across
my desk a few months ago came a beautiful cabochon cut ruby
looking stone. In fact it was certified by the Inidan
Gemmological Institute as a ruby! It started out as corundum
and was treated red. I had some of my gemmological students test
it and low and behold it had a few interesting properties not
congruent to a ruby. However, if someone did not have access to
having seen this stone, who knows what it would be called.


#8

Ron:

As far as I know, there is not an easy test in use that will
really reliably differentiate syn from real amy. You can look
for breadcrumb inclusions in the syn., and it used to be that if
you polariscoped and found twinning planes (and you often do) you
could reliably say it was natural. But I’m told that now they
make the syn with twinning. The syn I have seen looks, like most
synthetics, too good to be true and a little too saturated and
juiced up. That’s always a clue. But it’s a cheap stone that
doesn’t bear sending to the lab for sophisticated tests (I think
IR absorption is diagnostic and there are commercial labs which
will check parcels, but the cost is prohibitive). I think the
real solution is complete disclosure and a disclaimer that it was
sold to you as natural but there are virtually undetectable
synthetics. Unless you cut your own from rough that is obviously
a natural crystal. But would you want to be the first jeweler
on your block to do this? Some brave souls will and could make
it a marketing point that they educate the sophisticated
consumer. But your average impulse buyer in the mall is just
going to walk off if you tell her “you know, this might be
synthetic”.

When the spectrometers come down in price, people will buy them
and many of these problems will be less important as they ID
synthetics well.


#9
   Synthetic quartz is now grown using natural twinned "seed"
crystals resulting in twinned synthetics, according to the
literature..no longer a reliable test, I believe 

hi marty,

what they told me at gia, a long time ago, is that all synthetic
amethyst has the xtal twinning like you’re saying, and that the
twinned xtal in occurring in nature is rare but exists. so if
you are examining an amethyst in a poloriscope and it exhibits
xtal twinning, it is a good indication that the gem is a
synthetic. proof can be obtained by examining inclusions. also i
remember most of the birefrigent color in synthetics is blue
instead of violet. if this is wrong i would like to learn
something new.

best regards,

geo fox