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Heat-discolored emerald

Hope someone can help on this – A friend was asked to repair an
antique gold ring with a large emerald in it. she chose not to remove
the emerald, as the prongs old and becoming weak - she’s had it out
before to repair the ring, and had to repair some that broke when she
removed the stone. So she opted to use some of the heat shield typ
stuff (don’t know exactly what kind.) Anyhow, the emerald, while not
cracked or damaged in that respect, changed color to a dark ugly sort
of olive green. My question is – does anyone know whether or not the
original color can be restored? And if so, how?


Good move!!! Nothing will save an emerald from heat in my
experience…the only thing I can suggest is to soak it in
wintergreen oil. Otherwise it will make a nice reminder piece…

Good luck

What might have happened is that the emerald was oiled and the heat
caused the oil to change color. A second thing is that the emerald
was treated with a polymer, IE filled and that the filling changed
color. It is doubtful that the emerald itself changed color unless
the heat shield was useless. However, if there was enough heat to
attack the oil/polymers and turn them color, it might very difficult
if not impossible to complete remove them.

A word of caution here also. If the stone was treated with a
polymer/hardener like Opticon, attempts to remove it might damage a
weak stone. The epoxy (opticon) expands when it softens so you can
put a lot of internal pressure on a stone. I have had opal inlays
snap and crack when I removed them from a ring using Attack.

So what to do. I would remove the stone and then put it in a jar of
acetone or Attack. Let it set a couple days and then change the fluid
and let it set for another couple days. Hopefully this will soak out
the old filling material and leave you with a stone that is less
brown. Now you will need to refill the emerald with an oil or
polymer to get it back to it’s original color. If the stone is 30
years or so old, the chances are that it was an oil filling, but no

Good luck. Don

Margret , Many emeralds are oiled perhapsit can be retreated.


I think that once you heat an emerald ot aqua the change is perm.
Check with gia in Carlsbad, Ca. good luck rocky

Hi all; Yesterday I posted about having this emerald repaired by
Aurther Groom. I didn’t have the address at the time, but now I do.
If this is a large stone, or was initially an expensive one, I would
seriously consider having it repaired by a professional with plenty
of experience in this area. Here’s Groom’s address, give them a

Aurther Groom and Company, Inc. 579 Fifth Ave. #1600 New York, NY
10017-1917 Phone: 212-832-9100

David L. Huffman

The only person I’ve heard of who might be able to help you with this
problem is a man named Aurther Groom. What has probably happened is
that you’ve cooked a filler material used on the emerald. It could
be Ceder oil, or perhaps Opticon, a catalytic resin used to improve
an emerald’s appearance. Groom has a business removing the old
fillers in emeralds and replacing them with his own filler which he
claims is far superior to those used “in the wild”. Unfortunately, I
have no idea where to contact this man. Perhaps there is someone out
there in Orchidland who know how to reach him. Barring that, you
might contact the people Jeweler’s Circular Keystone (a trade
magazine) at and see if they have any record of his address
since I believe I saw an article on him there some time ago. Good
luck, I’m sure others here will have advice.

David L. Huffman

   large emerald in it. ...used some of the heat shield type
stuff.. Anyhow, the emerald, while not cracked or damaged in that
respect, changed color to a dark ugly sort of olive green. ...does
anyone know whether or not the original color can be restored?..if
so, how?

Since I get the Digest version, maybe some one else has already
responded to this query. I know Randy Smith did as he sent me a copy.

Firstly, your jeweler friend committed one of the “sins” of jewelers.
Probably 99.5% of all Emeralds are “oiled” (of course there are some
pure crystal Emeralds around that don’t need oiling - but mere
mortals like us rarely get to see them - for example, of the 300+
carats of faceted Emeralds that I had at the recent Tucson Show -
only 5 stones weighing a total of 5.02 carats fell into this category
and were selling at $2500 - $ 3000/carat wholesale).

The “oiling” of Emeralds is done to fill in the fractures and
inclusions with a material that has a Refractive Index close to that
of Emeralds and to make the defects seem less apparent. Up until
recently the industry required that the “oiling” process be
completely reversible. This means that the “oiling” is not permanent
and periodically has to be replaced. Common “oiling” materials
include (or have included in the past) Mineral oil, Palm Oil, Cedar
Wood Oil, Opticon Resin without hardener, Paraffin, and a whole range
of others. Some more permanent treatments include Opticon Resin with
hardener and UV cured photopolymers.

In order to safeguard this “oiling,” jewelers must not subject the
stones to heat, flame, steamers or put them into ultrasonic cleaners.
Also the unset stones should not be stored in stone papers or on
cotton as this will eventually pull out the “oiling” from the stones.

I was taken to a Bank Vault of a customer to see his very fine stones
(which he assured me were of much better quality than mine) and which
had been stored for a long period in stone papers in the temperature
and humidity controlled environment of the Bank. Needless to say the
"oiling" had pretty much gone out of the stones and they were quite
unattractive when he showed them to me.

By applying heat to the large Emerald stone, and depending upon what
heat shield material was applied, the minimum your jeweler friend did
was to make the “oiling” much more fluid and allow it to run out of
the Emerald and be soaked up by the heat shield material. Depending
upon the amount of heat applied, that is all that happened and the
"oiling" material can be removed and the oiling re done.

One basic problem is to determine exactly what material was utilized
for the initial “oiling” in order to utilize the correct solvent to
remove the original “oiling.”

Since you mention that it is a large Emerald, and may be a quite
valuable one, it might be interesting to have the Emerald treated by
a professional company specialized in removing and re-treating

One that comes to mind is the Arthur Groom Company in NYC that
advertises having developed a treatment for Emeralds that is
permanent and at the same time reversible. Apparently they can
discover what material was used in the original “oiling,” remove all
vestiges of the original material, treat the Emerald with their
"secret" formula and their treatment does not have to be periodically
repeated. The fact that their treatment is reversible means that in
the future a buyer can have the treatment removed from the stone,
examine the emerald in its natural state and have a certification
issued and then re-treat it. (I have no connection to this company)

“Gemtrat” address is Arthur Groom & Co. Ph (212) 832-9100. E-mail As per Mark Liccini, in his article on Emerald
Enhancements, Color & Light magazine, (International Gem Society) Vol.
1, Nr 2.

Here’s a quote from another e-mail list from the recognized authority
on Emeralds (and author) Fred Ward.

"Regarding emeralds and the chemical brews that are used to mask
inclusions, there are few long-lasting or permanent fillers. Arthur
Groom’s trademarked “Gematrat” treatment is guaranteed by Groom to be
permanent and if it ever fails he will replace it free “forever.” I
consider a hardened polymer to be permanent or almost permanent. That
doesn’t mean just swiping a little hardener over the filled fracture
but mixing hardener with the polymer. These may turn cloudy over time
or suffer other defects, but they last longer than the usual fillers
that evaporate and/or deteriorate in time. Unhardened polymers, such
as Opticon without the hardener, last only a few years. Oils, natural
or synthetic, are also short-lived.

Best regards Robert Lowe Lowe Associates - Brasil Gemstones, Rough,
Specimens Tucson, February 7 - 12, 2002 - GJX # 205 e-mail

** Hanuman’s Response **

Back in 1997 Ganoksin has published the Fred Ward’s Case "The Emerald
Case Line"

We also published the Gemlab Report about Emerald Oiling (In-Fill)

Hope you will find these article informative
Your host

All, If you turned your emerald browninsh by heat you have probably
burned a resin filler in the emerald. I have never heard of anyone
successfully removing the burned filler from an emerald and refilling
the emerald.

Gerry Galarneau

Aurther Groom and Company, Inc. 579 Fifth Ave. #1600 New York, NY
10017-1917 Phone: 212-832-9100

I have used his serevices and has worked miracles. You’ll probably
have to send the stone to get a good response. I also remember
talking to Yehuda(diamond fracture enhancers) and they were several
years ago researching working with emeraldsmbut don’t know where they
are in their work on emeralds.

Ron Kreml


I read the following message posted on your forum:

This thread also had me wondering about the economics of treating a
couple of stones I have. I sent off a note to Arthur Groom and
Company and here is the response I received

      Mr. Rogers Yes, we do enhance single stone. The cost to
enhance the emerald range from $50 to $100 per carat. It will take
approx. 2-3 weeks to finish. If you are interested, please send the
emerald to Clarity Enhancement Lab. 20 West 47th Street Suite 808,
New York, NY 10036. If you have any question, please call Mr.
Fernando Garzon at 212.730.8484. 
   Given the market on emeralds now, I am asking myself it
spending an additional $300 on a stone will really give me a
return.  I guess that there is no way to know the answer until you
see the results of the treatment is there.  I might be tempted to
send in a small stone to have something to gage the results by.  I
believe that Gems and Gemology ran a article on this treatment a
few issues back which had some before and after pictures. I need to
take a look at it again. 

I would like to say that Don seems to have missed the point of the
emerald treatment offered by Mr. Groom. The treatment, presently
called ExCel, does not fade, does not change, can survive an
ultrasonic, steam cleaner and re-polishing. Rather than worry about
how the stone will look, worry about how the stone will look in ten
years or more. Mr Groom’s process is guaranteed for life. yes, it
most definitely makes the emerald look the best. As one of his
competitors said, “The problem with it is that it makes the stone
look too good!” I would recommend to Don that he have it done and not
just look at the different it makes in the stone’s appearance but
also the assurance that he will have knowing the stone will not be
returned by a mad customer, ever!