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Amethyst Identification


#1

Jess,

I am glad you asked me more info about amethyst transparency to
UV light. When I answered to you at first I did refer to some of
my gemmological material courses and notes of two years ago as
well as an update on synthetic amethyst I received in september
97 (the latest didn’t mention the use of UV light as a method of
identification). This morning I contacted the gemmological
Institute from whom I received my courses and was informed that
the method they were refering to is no longer valid. Under LW/UV
light natural quartz is inert. Under SW/UV light you may see a
weak fluorescence. However fluorescent material can be added to
the process of synthetic quartz rendering the UV test unvalid. As
I spoke further to 3 of my fellow gemmologists most (not all) of
the synthetic amethysts you will come across to day will be
untwinned material, this will confirm that the amethyst is a
synthetic. Now we know that natural amethysts are of twinned
nature.

  1. Use the polariscope. Find the direction of the amethyst’optic
    axis, then position the stone in that orientation between the
    crossed polars of your polariscope. It is better to immerse the
    stone in a liquid close to quartz RI (1.54) but water is quite
    allright. If twinning is present you will find a number of
    paralleled and coloured interference bands. Most likely you will
    have in your hand a natural amethyst. However, this test is no
    longer absolutely positive!!! If there is twinning more
    identification is needed. Next…

  2. Look for INCLUSIONS for more positive identification.

UV light can be very helpful for identification of gems and
minerals, especially when the luminescing colour changes between
LW and SW. Many diamonds fluoresce blue under UV light and ALWAYS
fluoresce stronger under LW that SW. GGG has a none to moderate
orange under LW and a moderate to a strong pinkisk-orange under
SW. Synthetic Spinel has a strong to very strong chalky white or
yellowish under SW. Kunzite has a weak orange-pink under SW and a
strong orange-pink under LW. Opal has a white, green or yellow
under SW and blue or white under LW.

Have fun with your amethysts. Thank you, I have, for now, an
accurate chapter on amethysts in file.


#2

Francoise, Thanks for your imput to my original question of
identifying syn. Amethyst. Its amazing to see the thread of
I really enjoy this forum and exchange of
Keep it up all of you! Ron www.kreml.com


#3

Hi everybody

I don’t want to sound controversial and there must be others out
there like me so why all the fuss about trying to to tell
Amethyst from anything else. I’ve bought my share of the natural
type and even while in northern Ontario visited mines producing
tons of the rough, only to find everything hopelessly fractured
(from blasting). Be great though for my driveway.

All of the “man made” colored stones that I have ever cut have
turned out beautiful, and some cost only a few cents per carat,
while natural ? (enhanced, dyed, oiled, glass filled (that’s
natural ?) and a dozen other methods of treatment that we don’t
know about) cost far more, and one has generally to put up with
inclusions, fractures, foggy areas etc., then have to explain to
the customer why all of that make a better gem?.

I’m not high on the ladder of success in the jewelry business
(maybe that’s why I think like I do) but I when I show a
potential client the rough from which a particular stone was cut
the difference between what had been a piece of inert mineral
and the brilliant live gemstone they see is enough. If the
customer knows the origin of the stone and loves what he sees
that’s the bottom line.

I would guess that there are tons of gem rough out there that
the best of gemologist could not detect from natural that came
out of the ground, remember they always have to play catch-up and
will always be behind the times at detecting what any new
marerial is composed of.

The big difference is the $$$$$ potential. After all there is
more profit in selling a cadillac than a chevrolet, even if the
dealer just switched the hood ornament. Incidently I am not
connected in any way with suppliers natural or synthetic rough.


#4

Francoise:

I cannot thank you enough for your knowledgeable post on the
amethyst ID. It would have taken me much time searching through
the books, calling GIA, etc., to get the you
provided. I’m sure other list members will have a use for this
too.

There is an old saying here to the effect that your employer,
when he finds that you are the best worker, loads you up with
jobs while the other workers struggle with half your workload.
So, in that vein, I am going to ask if you have up to date info
about synthetic diamond ID. The only thing I have heard is that
the Hanneman wand was a good tool for those syn diamonds which
had magnetic properties. I’m would guess there are some
characteristic inclusions in synthetics, but I have not heard
whether they occur in all synthetics and I don’t know what they
are. I also heard or read somewhere that the test for magnetism
is no longer infallible. I am also wondering whether synthetics
of any size are actually showing up on the market. Any help you
can provide would be greatly appreciated. Thanks again.


#5

Leo:

I had something of an existential crisis after I started into
the jewelry/gemmology education when I realized that a lot of the
people buying jewelry are buying from less than the purest of
motives — greed, snobbery, conspicuous consumption. Beauty
figures into the equation, but certainly isn’t the only thing for
most. Those who are interested in attractiveness per se may
respond to your approach… While I would say that some of the
synthetics are too juiced up in color to look right, it does
seem to me that good hydrothermal emerald looks a lot better than
natural costing a whole lot more. However, rarity is definitely
a factor as is the simple dea that something came out of the
ground as opposed to out of a lab. Perhaps it doesn’t make
sense, but there you are — many things don’t.

As far as the synthetics not being detectable, it doesn’t seem
to be that much of a problem with many synthetic vs natural
determinations. The amethyst is the exception right now, but
there will be some test eventually, I would think. We will see
what will happen with syn diamonds.


#6
  As far as the synthetics not being detectable, it doesn't
seem to be that much of a problem with many synthetic vs
natural determinations.  The amethyst is the exception right
now, but there will be some test eventually, I would think.  We
will see what will happen with syn diamonds.

Visible range spectroscopy of De Beers’ diamond synthetics are
posted on my web site at http://www.gis.net/~adamas/debee
rs.html If visible range indicators are that of a synthetic
then fluorescence and cathodluminescence are typically
diagnostic…Visible range spectroscopy done at room temperature
with SAS2000
Spectrophotometer Analysis System

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
        So, in that vein, I am going to ask if you have up to
date info about synthetic diamond ID.  The only thing I have
heard is that the Hanneman wand was a good tool for those syn
diamonds which had magnetic properties.  I'm would guess there
are some characteristic inclusions in synthetics, but I have
not heard whether they occur in all synthetics and I don't know
what they are.  I also heard or read somewhere that the test
for magnetism is no longer infallible.  I am also wondering
whether synthetics of any size are actually showing up on the
market.  Any help you can provide would be greatly appreciated.
 Thanks again.

The De Beers synthetic diamond (colorless and colored) that I
examined in Johannesburg are going to be a problem. Magnetic
inclusions are of no help when the diamond is mounted. See
http://www.gis.net/~adamas/debee rs.html for a look at visible
range spectroscopy on 6 De Beers synthetic diamonds.

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