SLP Gem Lab..??

[colorluvr]

TL, another quick question while I have your attention (I hope). It''s about UGL appraisals

"I looked at your link, and it uses an appraisal from UGL, which I did a little searching on the internet for. UGL is the appraisal branch of EGL (another gemologial lab), and based on what I read on the net, their appraisals are highly inflated. Based on that, I personally wouldn''t trust them. "

You wrote this in another link a while back.... I have an emerald that has a UGL appraisal.... I realize the value is probably way over inflated, and that''s ok because I didn''t pay anything near what it says... my question is whether or not the info on the appraisal can be trusted...

ie... it says "traditional normal enhancement: cedar oil"

Do you think that can be trusted or should I have it looked at by someone else. I want to know what I have, not so much because I might have been taken (might have but it''s too late to do anything about it)... but I want to know whether or not to look at this stone for a "fun ring" ie, LOGR type setting, or whether I am going to wait until I can find a more expensive/special setting for it.
(not knocking LOGR, as I have several)

TIA for your opinion (and anyone else who would like to chime in)..

 

[T L]

Date: 6/1/2010 11:33:02 AM
Author: colorluvr
TL, another quick question while I have your attention (I hope). It''s about UGL appraisals

''I looked at your link, and it uses an appraisal from UGL, which I did a little searching on the internet for. UGL is the appraisal branch of EGL (another gemologial lab), and based on what I read on the net, their appraisals are highly inflated. Based on that, I personally wouldn''t trust them. ''

You wrote this in another link a while back.... I have an emerald that has a UGL appraisal.... I realize the value is probably way over inflated, and that''s ok because I didn''t pay anything near what it says... my question is whether or not the info on the appraisal can be trusted...

ie... it says ''traditional normal enhancement: cedar oil''

Do you think that can be trusted or should I have it looked at by someone else. I want to know what I have, not so much because I might have been taken (might have but it''s too late to do anything about it)... but I want to know whether or not to look at this stone for a ''fun ring'' ie, LOGR type setting, or whether I am going to wait until I can find a more expensive/special setting for it.
(not knocking LOGR, as I have several)

TIA for your opinion (and anyone else who would like to chime in)..

I personally wouldn''t trust the notation of enahncement on the UGL. I would probably only trust AGL to give the most comprehensive information on emerald enhancement. While I think it''s probably easier to check for polymers and other fillers vs oil in an emerald, the oil or the polymer chemical makeup might be in question (some are more stable than others). Also, check for surface cracks, if there are quite a bit of them, there''s the potential it has been greatly enhanced. However, the real big thing to be leary of with emeralds are the convincing synthetics on the market, and I''m unsure of how sophisticated the equipment has to be to determine if it''s natural vs synthetic. I am not an emerald expert, so I hope someone chimes in with more information about this.

 

[colorluvr]

thanks TL... I''ve seen lots of synthetic/lab emeralds (and I''m talking the higher end ones like Chatham) and this is definitely not a lab. The typical emerald inclusions are way too obvious and it''s not the same color (almost perfect) green of the labs. I''m confident that it is a real emerald, just not whether or not it has been filled, etc. I do have an emerald that has a resin filled face and it has the surface cracks that you are talking about, but I bought it pretty inexpensively quite some time ago, with the idea of putting it in a bezeled pendant.


I''ll probably have this one checked out further when I have the money for a setting....

 

[T L]

CL,
The thing is that the Chatham ones are obvious synthetics, but there are some emerald synthetics that have inclusions and look more like the real thing Again, I''m not an emerald expert, so determining one of the more convincing synthetics from a natural stone may be a more challenging effort.

 

[haagen_dazs]

if AIGS tests a gemstone as unheated, then it doesnt matter what kind of heat treatments the gemstone has right ? (just confirming)

 

[T L]

Date: 6/1/2010 5:47:29 PM
Author: haagen_dazs
if AIGS tests a gemstone as unheated, then it doesnt matter what kind of heat treatments the gemstone has right ? (just confirming)

Correct, if they have deemed it to be unheated, then there is no worry about diffusion. There are tell tale signs that a stone has not been heated, like certain types of inclusions.

 

[morecarats]

Date: 6/1/2010 11:19:35 AM
Author: colorluvr

Date: 6/1/2010 11:00:36 AM
Author: tourmaline_lover
As for buying sapphires on ebay, I think you have to be careful about sapphires you buy from ANYONE, whether they''re on ebay or not. If you do buy a sapphire from Mr. John Doe Seller, regardless if it''s ebay or not, make sure you get a lab report from a large lab with the equipment to test for diffusion, GIT (GIT can test for it from what people tell me), GIA, AGL, or GRS. Make sure it''s explained specifically on the report that it has been tested for foreign elements and that they were not found, in other words, gentle heating, or no treatment. As for my part, I think I will just not buy sapphires anymore. They are lovely, but too much of a headache, and the ever increasing undetectable treatments are too ''iffy'' for me. They can use other elements asside from beryllium to diffuse stones, so who knows what else they''re using on corundum. It''s very scary.

I totally agree.

Correct me if I''m wrong... if a lab, such as AIGS states that there is no indication of heat or any other treatment (in a sapphire), then I can feel more comfortable.. the problem is when they say ''heat'' because there is no way (without the expensive equipment) to tell if it is only gentle heat or the more aggressive treatments such as BE. Is that correct?

When it comes to heating sapphire, there is really no such thing as "gentle" heat. Heat treatment for sapphire is effective because rutile has a lower melting point than corundum, and it is the meliting of rutile that improves the clarity and the color (the latter through the release of titanium).

Rutile or titanium dioxide has a melting point of 1843 °C. If you think that is gentle heat, consider that the optimum temperature of ovens for cremating human remains is between 1600 and 1800 °C.

 

[T L]

This is not far from the temperature of the surface of the sun at 5700 C. So much for "gentle heat." I'm not sure how that phrase arose, but it is probably better to say traditional heat treatment, or something akin to that.

Morecarats,
Any suggestions?

 

[arjunajane]

Instead of starting a new thread, I thought I would continue here.

Morecarats, you mentioned earlier that BGL is second rate to GIA and GIT. Based on what I have now read up on and learned, I would not disagree.
However, I am wondering if there is an instance where you would say using a BGL cert with a photo as reliable?
Leaving aside problematic sapphires, can you please comment on obtaining BGL certs for gems such as spinel, garnet or tourmaline? Do they have the capacity to identify synthetics reliably?


TL or anyone else with info, please do post as well - any input appreciated.

 

[morecarats]

I have limited experience with BGL -- perhaps 100 stones over the last few years. My experience is that they will not issue a report unless they are sure of their identification. I have found that they are are unable to distinguish natural from synthetic quartz when presented with a clean sample, and that they are unable to certify any unheated sapphire. I have not had any cases where one of their reports was shown to be in error by another lab.

Since BGL doesn''t have any advanced instruments, they can''t do any analysis that depends on chemical composition (such as copper-bearing tourmaline) or spectroscopic data. They are not currently capable of detecting beryllium diffusion of corundum.

I don''t know if they have any experience detecting some of the new spinel synthetics. Basically they do the job that a trained gemologist can do with traditional instruments. When I''ve visited either of their two small locations in Chanthaburi they seemed to have students working there under the supervision of a graduate gemologist.

 

[arjunajane]

Date: 6/5/2010 6:26:41 AM
Author: morecarats
I have limited experience with BGL -- perhaps 100 stones over the last few years. My experience is that they will not issue a report unless they are sure of their identification. I have found that they are are unable to distinguish natural from synthetic quartz when presented with a clean sample, and that they are unable to certify any unheated sapphire. I have not had any cases where one of their reports was shown to be in error by another lab.


Since BGL doesn''t have any advanced instruments, they can''t do any analysis that depends on chemical composition (such as copper-bearing tourmaline) or spectroscopic data. They are not currently capable of detecting beryllium diffusion of corundum.


I don''t know if they have any experience detecting some of the new spinel synthetics. Basically they do the job that a trained gemologist can do with traditional instruments. When I''ve visited either of their two small locations in Chanthaburi they seemed to have students working there under the supervision of a graduate gemologist.

Thankyou MC for the quick answer, that is very informative and helpful.

Can you please clarify one thing for me? What do you mean by ''they are unable to certify any unheated sapphire'' ?
(please excuse if this is a daft question!).

 

[morecarats]

I mean when presented with an unheated sapphire they are unable to issue a report that certifies the stone as unheated. My impression is that they lack confidence in their ability to analyse inclusions and internal structures under the microscope, and they don''t want to issue a report which will turn out to be incorrect.

 

[arjunajane]

Date: 6/5/2010 6:44:37 AM
Author: morecarats
I mean when presented with an unheated sapphire they are unable to issue a report that certifies the stone as unheated. My impression is that they lack confidence in their ability to analyse inclusions and internal structures under the microscope, and they don''t want to issue a report which will turn out to be incorrect.

right, gotcha.
Hrmm..I guess that is good that they don''t want to issue a false report..
But more bad that they don''t have enough skill to provide such an analysis

Thanks again MC for all the info, this thread has been a great eye-opener.

 

[Muhammad_Ali]

I’ve never heard of this lab nor dealt with them. I wonder if it is like the IGI of the diamond grading lab where it is very common and usually worthless... Like TL, why not suggest AIGS to the vendor since this lab is also in Thailand and is far more reputable with full testing?

I definitely wouldn't say IGI certified diamonds are "worthless," the general rule of thumb is if IGI gives it a "VS2", GIA would give it a "SI1-2".

Lotus is also an excellent Thai lab.

 

[T L]

I definitely wouldn't say IGI certified diamonds are "worthless," the general rule of thumb is if IGI gives it a "VS2", GIA would give it a "SI1-2".

Lotus is also an excellent Thai lab.

If you want to make sure you're paying a fair price for a diamond, or you're buying a very rare colored diamond, then a GIA lab report is a must. If you're buying a second hand average diamond for a bargain price, then I suppose IGI will suffice, but always assume the grading is far more generous then reality.

 

[Muhammad_Ali]

If you want to make sure you're paying a fair price for a diamond, or you're buying a very rare colored diamond, then a GIA lab report is a must. If you're buying a second-hand average diamond for a bargain price, then I suppose IGI will suffice, but always assume the grading is far more generous than reality.

Absolutely, if the value is over $3,000, demand SSEF, Gubelin, GIA, GRS, AGL, etc. (ideally GIA for diamonds, AGL prestige grading for colored stones). IGI is okay for average colored stones and diamonds. I can vouch for the overstated grading personally; GIA would never give a heavily included diamond anything above "I1/2", yet I've seen IGI stones that are opaque with SI2 gradings.