Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Wed Dec 28, 2016 7:13 pm
Moderator: Lapidary Diamonds
Joined: Mon Aug 20, 2012 11:32 pm Posts: 1747 Location: Florida, United States
Miguel wrote:
Hello everyone, The Excel and Gematrat Emeralds Permanent Treatment, for MINOR clarity enhancement, is acepted and desirable for the trade? I will appreciate your opinions. Thank you
Please provide links to descriptions of these treatments.
Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Wed Dec 28, 2016 8:30 pm
Moderator: Lapidary Diamonds
Joined: Mon Aug 20, 2012 11:32 pm Posts: 1747 Location: Florida, United States
"ExCel is a polymer with the refractive index similar to an emerald. It is capable of withstanding ultrasonic baths, steam cleaning and the re-polishing process without any changes to its appearance. It is also removable if needed without any adverse effect to its host stone."
All right. If you have an emerald treated by this process to make the stone appear less flawed, then if you put it up for sale, you are legally obligated to declare the stone as treated to enhance clarity.
I found this link: http://www.emeraldstone.com/treatments.html Gematrat and ExCel were both developed at Arthur Groom lab. So, both must be declared as treated to enhance clarity when offered for sale.
"ARTHUR GROOM GEMATRAT & ExCel The Arthur Groom lab of New York supplies a enhancement for your emeralds which is a newly developed improvement on opticon. According to Mr. Groom his enhancement will not turn yellow. The benefit as well is that it will not leak out of the stone and he claims that you can steam clean or ultrasonic this emerald without ever losing the enhancement. Gematrat does not color stones. Gematrat has a refractive index that is very close to that of true emerald. In this regard AG used to provide a UV tracer for detection but has recently felt this was not necessary. AG's newest improved enhancement is called ExCel. ExCel's latest version as of May/03 is nicknamed "1.52" in an effort to show how its refractive index is similar to that of cedar oil and now lower than his previous Gematrat. Code: E-Colorless-Resined"
The emeralds are certificate by recognized gemological labs.
But my question is: For high clarity Emeralds (Insignificant or Minor), I can substitute the traditional oiling treatment, for the modern Excel or Gematrat treatment? It is ok for the market?
I test with an emerald, with gem lab certificate clarity enhancement MINOR, that emerald was treated with traditional oiling. On that same emerald, I changed the traditional oiling treatment for the modern Gematrat treatment and the emerald appearance improve. And it remains clarity enhancement MINOR, but the emerald look best, more eye clean, more luster and the treatment is more permanent
Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Thu Dec 29, 2016 4:21 pm
Gemology Online Veteran
Joined: Mon Jun 16, 2014 1:10 pm Posts: 850
Miguel wrote:
Yes Tom,
The emeralds are certificate by recognized gemological labs.
But my question is: For high clarity Emeralds (Insignificant or Minor), I can substitute the traditional oiling treatment, for the modern Excel or Gematrat treatment? It is ok for the market?
I test with an emerald, with gem lab certificate clarity enhancement MINOR, that emerald was treated with traditional oiling. On that same emerald, I changed the traditional oiling treatment for the modern Gematrat treatment and the emerald appearance improve. And it remains clarity enhancement MINOR, but the emerald look best, more eye clean, more luster and the treatment is more permanent
Do you have pictures?
I am just a collector - I would prefer an untreated emerald if high clarity and an traditional oiled stone is o.k. for me.
No, I haven't Emeralds Images. All my Emeralds are traditional oiling. I just test the Gematrat treatment on one Emerald. And yes, it looks more cleaner to the eye
Regarding, the Untreated (no oil) Emeralds, eye clean, very transparent quality, with many luster, Yes, they are beautiful, rare, scarce and expensive!!!
Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Fri Dec 30, 2016 1:04 am
Gemology Online Veteran
Joined: Mon Jun 16, 2014 1:10 pm Posts: 850
Miguel wrote:
Dear Marlow,
No, I haven't Emeralds Images. All my Emeralds are traditional oiling. I just test the Gematrat treatment on one Emerald. And yes, it looks more cleaner to the eye
Regarding, the Untreated (no oil) Emeralds, eye clean, very transparent quality, with many luster, Yes, they are beautiful, rare, scarce and expensive!!!
I know - I collect rare gems which are much rarer then an untreated fine emerald and I am fine with smaller but top quality stones.
A friend of mine has customer who want "untreated" stones. Does it make sense to treat an emerald with a high clarity only for a bit better look? Or accept and enjoy an untreated piece of nature.
Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Sat Dec 31, 2016 7:10 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
I think the American Gem Lab, specifically Chris Smith, has defined this well. AGL classifies the various types of filler substances into two broad categories: Traditional and Modern.
Chris Smith wrote:
Those materials that are classified as traditional include various types of oils (such as Cedarwood and many others), waxes (such as Paraffin) and natural tree resins (such as Canada Balsam). In contrast, those materials classified as modern include the various petroleum derived polymer-type resins, which may be marketed under many different names (such as Opticon, Palm Oil or Palma, Gematrat and ExCel, as well as others).
Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Mon Jan 02, 2017 8:28 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
I'm a little confused. Does the LMHD classification simply differentiate between classic (oil, wax, balsam) and petroleum derived polymer-type resins? Like Type 1 and Type 2.
I'm a little confused. Does the LMHD classification simply differentiate between classic (oil, wax, balsam) and petroleum derived polymer-type resins? Like Type 1 and Type 2.
The Colombia Treatment labs, normally use two treatment types:
1- A mix of Cedar oil and Resin, type liquid, lab report:
F1-F2-F3
2- A mix of Hard Resins, type Hard, permanent (Gematrat), Lab report:
C1-C2-C3
Some times, an Emerald, treated with hard resin, with very low clarity enhancement, without cavities and/or wide fissures, the lab report could give F1
This is my personal opinion, each lab have different grading policies
Post subject: Re: Excel and Gematrat Emeralds Permanent Treatment
Posted: Mon Jan 02, 2017 10:09 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
I'll rephrase. According to LMHC: The type of filler is of little consequence, the amount is the issue. I still prefer AGL's style of reporting. Documenting the amount of filler along with the identification of filler. It seems that some of the petroleum polymers may actually be preferable to the "classic" fillers.
I agree with Miguel that different labs have different protocols. What influence or authority does LMHC have internationally?
In my personal opinion, nowadays, is very difficult to find an Emerald treated with natural, organic filler, most of cedar oil at the market is manufacture by the labs, with some inorganic substances, is not 100% naturald cedar oil.
Also, most of the treatment labs, for oiling Emeralds, use a mix of cedar oil and some inorganic sustances, like liquid resin, in order to improve the treatment R.I.
Yes!!! AGL is an excellent lab for Colored Gemstones
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