AGS0 trumps HCA?

[WillJohnson]

Hello all,

I am currently looking at WF ACA and ES RB's and was wondering if I should really worry about their HCA scores. Since they are all graded AGS0 ideal, does that mean that their light performance will be very similar (excellent), or is a 1.5 on the HCA still better than a 1.9?

 

[diamondseeker2006]

AGS0 trumps the HCA. I never, ever use the HCA on AGS0 stones because AGS has evaluated the stone for light performance and has found it to be ideal..the best. So the HCA is really to use to screen GIA Excellent cut stones because that is a much broader cut category than AGS Ideal cut.

 

[yssie]

AGS0 trumps the HCA. I never, ever use the HCA on AGS0 stones because AGS has evaluated the stone for light performance and has found it to be ideal..the best. So the HCA is really to use to screen GIA Excellent cut stones because that is a much broader cut category than AGS Ideal cut.

I would disagree about generalising re. AGS0s, but with WF's ACA and ES lines specifically, or any other PS vendor brands cut for cut, absolutely - no need for HCA when you have pics, scans, and excellent pedigree.

 

[Dreamer_D]

"AGS0 trumps HCA?" Yes.

Further, 1.5 is not better than 1.9. HCA is a dichotomous rejection tool. Under 2 means evaluate further.

 

[yssie]

"AGS0 trumps HCA?" Yes.

Edit - yes, I worded it poorly. I agree that AGS0 trumps HCA.
I do not agree that AGS0 means no further review necessary, or that AGS0 automatically means winner.
Unless we're talking AGS0 + pics + IS + pedigreed cut-for-cut line, in which case it pretty much is just pick one.

 

[Gypsy]

"AGS0 trumps HCA?" Yes.

Edit - yes, I worded it poorly. I agree that AGS0 trumps HCA.
I do not agree that AGS0 means no further review necessary, or that AGS0 automatically means winner.
Unless we're talking AGS0 + pics + IS + pedigreed cut-for-cut line, in which case it pretty much is just pick one.

I disagree. If you are looking for a hearts and arrows diamond or something with precision patterning, then sure get the pedigree.

But an IS is largely redundant to the AGS0, IMO. I would be fine buying an AGS0 without an IS and recommending that someone else does so.

If all you are looking for is a diamond with great light return then I think AGS0 without anything else is fine. Not everyone sits there and examines the hearts image to see if the patterning is .001mm off or needs to.

 

[yssie]

"AGS0 trumps HCA?" Yes.

Edit - yes, I worded it poorly. I agree that AGS0 trumps HCA.
I do not agree that AGS0 means no further review necessary, or that AGS0 automatically means winner.
Unless we're talking AGS0 + pics + IS + pedigreed cut-for-cut line, in which case it pretty much is just pick one.

I disagree. If you are looking for a hearts and arrows diamond or something with precision patterning, then sure get the pedigree.

But an IS is largely redundant to the AGS0, IMO. I would be fine buying an AGS0 without an IS and recommending that someone else does so.

If all you are looking for is a diamond with great light return then I think AGS0 without anything else is fine. Not everyone sits there and examines the hearts image to see if the patterning is .001mm off or needs to.

I'm not talking about H&A or any other patterning. There are AGS0s that I definitely would not recommend, not to someone who is looking for "great light return" - doubly so actually because they'd be paying the AGS0 premium. They aren't ever going to be *ugly* stones, but they're not what I would consider "ideal".

It is uncommon but it does happen, and as such I disagree with the practice of suggesting that AGS0 is infallible, and that the stone need not be checked further. If a consumer is specifically looking for a stone with specific characteristics - a great RB by PS standards, say (no "excess leakage" as per common PS terminology, those faultlessly red ISs, etc.) then that consumer should always put in the effort to have each stone evaluated on its own merits (either have it looked at by someone trusted or look at it in-person, or get some pictures/scan) and not blindly trust in any given tool or grading system, because there isn't a single one that's going to deliver precisely to requirements 100% of the time.

To clarify - I am not talking about pedigreed lines like ACA, ES, BGDSignatures, GOGSignatures, Infinity, HoF, Solasfera - all of those are cut for optimal light return and with those I do think you can just go in and pick one and be assured of great light return. I'm talking about any old AGS0 you might see in an inventory somewhere - AGS0 by itself is no assurance of anything other than AGS0.

If all the buyer wants is "sparkly" then I agree that GIA + HCA or AGS0 by itself is good enough.


I posted these in an older thread -

AGS0 DQD http://www.jamesallen.com/diamonds/I-SI2-Ideal-Cut-Round-Diamond-1355422.asp


AGS0 DQD http://www.jamesallen.com/diamonds/E-VS1-Ideal-Cut-Round-Diamond-1389957.asp


AGS0 DQD http://www.jamesallen.com/diamonds/G-SI2-Ideal-Cut-Round-Diamond-1450982.asp
35/41.4/57.6/79
[/quote]

 

[diamondseeker2006]

Yssie, I remember you posting that before. But is it your belief that these "bad" AGS0's are common enough to worry about? Obviously the thorough vendors pre-screen and only have great ones, but I haven't personally come across one that looks that bad when I have looked through drop shipper inventories for diamonds for people.

I will add that I would have ruled out the diamonds above based on the angles and it would have worked to eliminate them.

 

[yssie]

Yssie, I remember you posting that before. But is it your belief that these "bad" AGS0's are common enough to worry about? Obviously the thorough vendors pre-screen and only have great ones, but I haven't personally come across one that looks that bad when I have looked through drop shipper inventories for diamonds for people.

I will add that I would have ruled out the diamonds above based on the angles and it would have worked to eliminate them.

It's not that I worry about it, just that I always think it's best to examine (or have someone you trust look into) every stone you're (generic you) seriously considering. As you say, looking at the angles (or using HCA) would eliminate those - but one has to actually *look* at the details on the report and the other info available - since we have JA's photos - and not just assume AGS0 = good to go automatically. Most of the time AGS0s w/o more info are going to be from drop-shippers, like you say, so that just confirms the importance IMO.

 

[0-0-0]

AGS0 trumps in the sense that it is given based on a lot more information than what goes into the HCA. But I think it's important to remember that AGS0 covers a range of stones just like GIA Ex, albeit a slightly different and perhaps smaller range.

IMO, not all AGS0 are equal as there will always be cutters and vendors that target the minimum AGS0 requirements for the marketing and price premium, just as some do for GIA Ex.

In the context of branded cuts, I don't think you have anything to worry about with WF/BGD/GOG/HPD. The vendors are confident enough with the stone that they are willing to offer buyback and trade in policies and keep the stone as in house inventory after all. But I must say there are some ES and Blues that I would not buy as I'm super picky about under table leakage and girdles.