Are AGS certs vastly superior? Or is it just me?

[vadar]

I''ve noticed that if I search on other (non-pricescope

) search engines for "Ideal" cut diamonds, there are TONS more matches as opposed to a pricescope search for AGS0 diamonds only. But when I plug the data from these supposed Ideals into the HCA, I get results often over 4... Is AGS just that much more accurate? I was under the assumption that AGS and GIA were pretty comparable, but even the GIA results I get for an "ideal" cut search end up being poor compared to an AGS0 only search. It would take forever to pull up each and every cert and check the HCA results, should I just stick with AGS, specifically AGS0 ONLY?

 

[stone-cold11]

Basically, GIA Ex grading includes a larger range of crown and pavilion angles that could results in light leakage resulting in higher HCA score. AGS grading are tighter and the cut grading are performance based on simulation of light rays behavior on the exact physical dimensions of the actual stone, thus resulting in better HCA scoring.

But that comes with a slightly higher premium for the AGS stones.

 

[Lorelei]

Date: 12/1/2008 3:47:46 PM
Author:vadar
I've noticed that if I search on other (non-pricescope

) search engines for 'Ideal' cut diamonds, there are TONS more matches as opposed to a pricescope search for AGS0 diamonds only. But when I plug the data from these supposed Ideals into the HCA, I get results often over 4... Is AGS just that much more accurate? I was under the assumption that AGS and GIA were pretty comparable, but even the GIA results I get for an 'ideal' cut search end up being poor compared to an AGS0 only search. It would take forever to pull up each and every cert and check the HCA results, should I just stick with AGS, specifically AGS0 ONLY?

AGS have very strict standards for cut grading, GIA cut grading can allow for some less desirable combos such as angular steep deeps for example which may not be the best performers, to get an Excellent cut grade for example. Also GIA rounds the numbers so there can be some variance. There are some superb stones to be found among the various GIA cut grade levels, you just might need to do a bit more work to find the best ones, whereas AGS are considered to be the gold standard for cut grading.

If you want all the info at your fingertips to include HCA scores, then use the search by cut feature as this should have that info available right there - you can find it here,

 

[Regular Guy]

Vadar,

I'm afraid we are probably talking: apples, oranges, and bananas.

Stone & Lorelei are effectively helping you discern apples from oranges, and my initial response to you, from reading your thread's title only, was to suggest you moderate your term "vast" to understand the difference between AGS & GIA, which have important variation between them, but not vast. Note...skilled practitioners...like Jonathan at GOG help to narrow the gap.

But, you've talked about the AGS0 control on the price search tools here. That's a banana.

Read this for background.

Prior to writing here, I pinged Admin for assistance, as I think there's some confusion about how to identify stones that come with AGS zero certification. To do that...what I do is check one of the 3 boxes that allow you select between GIA, AGS and other...selecting AGS only. And...then I look for the certificate, on line, that shows it has a zero. Using the other box, checking it for AGS0...gets you something that...from what I've read here recently...continues to bring back references to data with categories that are no longer in use.

(edited to add)...new, different...but related. In the "search by cut" info base, 5 columns over from the left, you get a "calculation" of what AGS score is associated with the diamond. On what basis is that calculation done? Dollars to donuts...it is a built in calculation that is only correct as of the AGS formula from over 3 years ago.

 

[vadar]

Date: 12/1/2008 4:37:32 PM
Author: Regular Guy
Vadar,

I''m afraid we are probably talking: apples, oranges, and bananas.

Stone & Lorelei are effectively helping you discern apples from oranges, and my initial response to you, from reading your thread''s title only, was to suggest you moderate your term ''vast'' to understand the difference between AGS & GIA, which have important variation between them, but not vast. Note...skilled practitioners...like Jonathan at GOG help to narrow the gap.

But, you''ve talked about the AGS0 control on the price search tools here. That''s a banana.

Read this for background.

Prior to writing here, I pinged Admin for assistance, as I think there''s some confusion about how to identify stones that come with AGS zero certification. To do that...what I do is check one of the 3 boxes that allow you select between GIA, AGS and other...selecting AGS only. And...then I look for the certificate, on line, that shows it has a zero. Using the other box, checking it for AGS0...gets you something that...from what I''ve read here recently...continues to bring back references to data with categories that are no longer in use.

Thanks so much for the informative (and eloquently written) links!

Luckily, I have been searching as you suggest, excluding the AGS0 box, just filtering for excellent cut, and including AGS and GIA. So it just happens to be that very few GIA stones meet my criteria, for "excellent" cut filter. I find this odd, considering your assertion that GIA represent the bulk of the stones out there.

 

[stone-cold11]

Date: 12/1/2008 4:58:38 PM
Author: vadar


Thanks so much for the informative (and eloquently written) links!

Luckily, I have been searching as you suggest, excluding the AGS0 box, just filtering for excellent cut, and including AGS and GIA. So it just happens to be that very few GIA stones meet my criteria, for 'excellent' cut filter. I find this odd, considering your assertion that GIA represent the bulk of the stones out there.

I am assuming you are using the cut quality search tool on PS which uses the HCA score for what is considered excellent and not just the lab grading.

EDT:
Also, in the cut quality database, most of the stones in there are preselected by the vendors, most of them are H&A and graded by AGS as more data, aka. the crown and pavilion angles are needed for the HCA　ｃａｌｃｕｌａｔｉｏｎ，　ｍｏｓｔ　ｖｅｎｄｏｒｓ　ｐｒｏｂａｂｌｙ　ｃｏｎｓｉｄｅｒ　ｉｔ　ｎｏｔ　ｗｏｒｔｈ　ｔｈｅ　ｔｒｏｕｂｌｅ　ｏｆ　ｌｉｓｔｉｎｇ　ａｌｌ　ｔｈｅ　ｒｕｎ　ｏｆ　ｔｈｅ　ｍｉｌｌ　ｓｔｏｎｅｓ. The few GIA stones are probably ｆｒｏｍ　GOG.　　Ａｌｓｏ　ａｌｌ　ｏｆ　ｔｈｅ　ｄｒｏｐ　ｓｈｉｐｐｅｒｓ　ｄｏ　ｎｏｔ　ｌｉｓｔ　ｏｎ　ｔｈｅ　ｃｕｔ　ｑｕａｌｉｔｙ　ｓｅａｒｃｈｅｓ．　　Ｏｎｌｙ　ｉｎ　ｈｏｕｓｅ　ｓｔｏｎｅｓ　ａｒｅ　ｉｎ　ｃｕｔ　ｑｕａｌｉｔｙ　ｓｅａｒｃｈｅｓ．

 

[vadar]

Date: 12/1/2008 5:08:23 PM
Author: Stone-cold11

Date: 12/1/2008 4:58:38 PM
Author: vadar


I am assuming you are using the cut quality search tool on PS which uses the HCA score for what is considered excellent and not just the lab grading.

Right. For the criteria I search, I seem to get more AGS results than GIA... Which is strange if GIA is the most popular lab.

 

[Regular Guy]

Date: 12/1/2008 4:58:38 PM
Author: vadar

Luckily, I have been searching as you suggest, excluding the AGS0 box, just filtering for excellent cut, and including AGS and GIA. So it just happens to be that very few GIA stones meet my criteria, for ''excellent'' cut filter. I find this odd, considering your assertion that GIA represent the bulk of the stones out there.

It''s important to get the right set of Venn diagrams going. If you are using the "excellent" cut filter, you are using the search by cut utility...dominated by in-house diamonds...which may be weighted heavily for AGS.

The bigger database here...the Pricescope your Diamond tool above...or the other version I like to start with...here...is the vaster set you''re talking about...where you can''t select excellent.

The Price Stats tool, above under Prices, or here...provides some moderated leverage...but includes lots of EGL stuff, and other undefined data.

No one ever said it was easy to save money.

 

[vadar]

So you just opened up the floodgates

If I put in the "AGS0" measurement criteria (58.7–62.3% depth, 53–58% table), I get a ton of results. So now I have to go through each of these, see if there is a cert, and see if it holds up in the HCA... The first one I tried scored a 1.6 based on the GIA cert and is about 600 bucks cheaper than the AGS in-house diamond I''ve been looking at (although it''s 0.05 carats smaller). Looks like I''ve got work to do.

 

[Regular Guy]

Date: 12/1/2008 5:28:29 PM
Author: vadar

If I put in the ''AGS0'' measurement criteria (58.7–62.3% depth, 53–58% table), I get a ton of results.

Although this is both reasonable & recommended...it, too, is probably obsoleted by the new criteria for earning AGS0. But it''s something. By the way, to Andrey as well...Leonid fingerpainted with the idea of adding a column in the bigger "Pricescope your Diamond" database...where at least diamonds that earned either "Excellent" or "ideal" on their certification were identified...but this seemed to only remain an idea (documented here, still).

So now I have to go through each of these, see if there is a cert, and see if it holds up in the HCA... The first one I tried scored a 1.6 based on the GIA cert and is about 600 bucks cheaper than the AGS in-house diamond I''ve been looking at (although it''s 0.05 carats smaller). Looks like I''ve got work to do.

Yes...or consider sharing the wealth. Read below my signature, my first link, where I suggest a strategy B. Primarily, WF offers this option, where you can have a "bird in the hand" with an in-house option, and also, can partner with them (ostensibly...I haven''t done this...but is should work) to find another option they''d bring in that...on its apparent merits, might be worth going for instead. The idea is of getting the buy in of the vendor...who understands they''ll be getting your business regardless...so maybe they''ll help you save money, too.

Very possibly...they can see data presented on these other virtual diamonds you can''t.

Anyway...you''ve got the idea.

Warmest regards,

 

[vadar]

thanks again. Seems like a good idea to have them pull the 3rd party certs, I don''t want to exclude anything solely on the basis of it not being in house. Although I suppose that has it''s merits, as they can confirm the eye-cleanliness. But I think 3rd party may provide the best bang for the buck; I''m seeing H''s for the same price as I''s and J''s, all things being equal (which they may not be - need the rest of the info on the certs).

I''ve seen a few potential ones that actually show up 3 times in a row on the results, I''m fairly certain I''m looking at the same stone since the measurements and other criteria are exactly the same, the only difference being a few bucks depending on the vendor.

 

[Regular Guy]

Date: 12/1/2008 5:54:21 PM
Author: vadar

I''ve seen a few potential ones that actually show up 3 times in a row on the results, I''m fairly certain I''m looking at the same stone since the measurements and other criteria are exactly the same, the only difference being a few bucks depending on the vendor.

Yes.