AGS vs GIA vs EGL Certs - Novice seeking advice

[CB1106]

Hi there! I''ve been reading for awhile and I''m a little confused. I noticed that a lot of the diamonds that are discussed here in the forum have AGS certs and sometimes both GIA and AGS.

My boyfriend and I have been looking at diamonds for a few months. We found that most of the GIA certs don''t include the pavillion and crown %''s. How would you know, from that alone, what you are looking at? Is there some way to calculate it out?

This is too confusing!

 

[Colored Gemstone Nut]

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On 12/28/2003 10:00:07 AM CB1106 wrote:











(Hi there! I've been reading for awhile and I'm a little confused. I noticed that a lot of the diamonds that are discussed here in the forum have AGS certs and sometimes both GIA and AGS.)


GIA & AGS are both reliable labs. AGS graded diamonds tend to fetch little more of a premium because in grading they publish the proportions of the stone.


GIA does not list all the measurements, rather the Depth and Table.

My boyfriend and I have been looking at diamonds for a few months. We found that most of the GIA certs don't include the pavillion and crown %'s. How would you know, from that alone, what you are looking at? Is there some way to calculate it out?

This is too confusing!


You can get a sarin report run on your diamond which will list this for you. Some vendors provide this information for you and you should be able to request a report if one is not provided.. Another idea is to have the stone appraised before purchase and the appraiser can run your diamond and also give you an un-biased 2nd paty opinion on your purchase....



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[valeria101]

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On 12/28/2003 10:00:07 AM CB1106 wrote: We found that most of the GIA certs don't include the pavilion and crown %'s. How would you know, from that alone, what you are looking at? Is there some way to calculate it out?
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No GIA certs include these extra measures. And I have no idea whether your seller can provide a Sarin report. But,


I guess you can still ask at least for the crown and pavilion as %: these can be measured (or rather estimated) with far less technology. However, if light return is what you are after, than there may be an even easier way to get a better look at a certain stone. How about getting a H&A viewer and/or Ideal Scope image of the diamond? This can even be a better indication of the optical performance of the stone given that the piece may not fall within H&A parameters at all or the crown/pavilion data may not represent the stone accurately (measurement errors and bias and symmetry defects coming into play).




These being said: yes a Sarin report will provide the most numbers. In my humble opinion, it is safer to rely on direct light return evaluation when judging a certain stone (rather than shifting though lists). What all these tests are? Surely you have seen the endless diamond analysis available on Jonathan's (Good Old Gold) site...

Hope this helps a bit... best of luck!

 

[Mara]

My opinion is that I would not buy a stone without the angles, or a Sarin....why..when there are so many stones that have them (e.g. AGS certs) or vendors that are willing to get them for you. Shop smart!

Good luck.