Excellent cut but bad HCA results?

[jdhunter]

Hello, I have purchased an engagement ring (but still have time to return if needed) and compared it to several other rings and I liked it best. It came with a GIA report and a Sarin report. Both suggest that it has an ideal cut. However, when I tested it with the HCA, it came up as a 2.9. I expected it to be much lower and am worried that maybe I am overrrating the brilliance of the stone. Does anyone have advice on the accuracy of this test. I am leaning towards the reality that maybe this is not the ''perfect stone'' that I think it is.

Here is the Sarin information if it helps:

Round Brilliant
D Color
VVS1
1.54 ct
Diameter: 7.43 (7.4-7.45)
Crown Angle: 35
Crown Height: 15
Pavil Angle: 41.1
Pavil Depth: 43.5
Cutlet: 0.3%
Table size: 56
Total Depth: 61.8
4.59mm
Girdle Thickness: 1.1-1.6
Proportion: 0 Ideal

 

[valeria101]

Nothing is perfect... including the HCA.

There are more precise ways to evaluate brilliance. For what that matters the numerous such cut grading tools and systems do not agree, and you are not likely to find anything that would score tops everywhere (and if you do, that might be one odd duck too!).


IMO, it is not realistic to seek 'perfection' in diamonds. Perhaps those things diamonds get to represent are indeed perfect moment, memories etc. these things are bits of polished rock.


My 2c

 

[belle]

hey jdhunter

welcome to ps!
there isn''t a piece of paper, a piece of machinery or even another person that can tell you whether or not you think your diamond is beautiful. if you were able to compare many diamonds and this was the best in your eyes, then there shouldn''t be anything left to question. hca isn''t a ''test'' of diamond beauty. it makes estimations based on given proportions. i can tell you that if the pavilion angle on your stone was in the 40.7 range, you would have very different results.

 

[JDgirl]

The diamond that will be in my ring is recommended as one not to buy by the HCA. It is an OEC. And I think it''s the most beautiful stone I''ve ever seen. And that''s what matters the most.

 

[Regular Guy]

JD,

Since you''re here (sorry no one responded a couple hours earlier), no reason not to at least carry forward with your due diligence...especially since...I presume you''re purposely intending to get the premier color and clarity as well. Seems like the stone should not have been represented as AGS0 to begin with, based on represented proportions, but I''m not an expert.

I''d say find a diamond that does fit the 0-2 HCA mold, and judge for yourself. You''re probably paying a pretty penny, have noted you can return it, and should be satisfied. It''s possible the sarin is mistaken, and performs better than they suggest. Though HCA could be off...minor facets could compensate(?), and/or it''s really a "very good" score, anyway. Still, a comparison to another diamond that comports to 0 - 2 will set you at ease, if you can accomplish this. Where are you? Typically, diamonds are well cut from Hearts of Fire, and Tiffanys, if you can find those nearby. Going to AGS''s web site to find who locally does carry options certed from AGS could help you as well.

Just here to support your proof checking, if you''re so inclined.

Regards,

 

[jdhunter]

Thanks so much you guys!! I really appreciate the honest feedback. I am in a bit of a dilemma in that I am not sure if I am just ''outthinking myself'' on this one. I did take the ring to Tiffany''s and compared it against a similar diamond and it was very slightly ''darker'' and with perhaps slightly less sparkle, but not significantly so. And the Tiffany diamond was $3000 more for 1.25 ct versus the 1.54ct I purchased. However, I wasn''t sure of the Tiffany diamond cut, dimensions, etc.. so it was hard to know if that was a good cut. And unfortunately I do not have a Tiffany''s nearby.

I know this is a once in a lifetime purchase, so I just want to make sure I get the most beautiful diamond possibly, particularly since it is going to cost $25,000 or so! And sometimes I feel a little blind to different levels of beauty and brilliance of the diamonds, but I''m sure my future fiance will definitely appreciate the difference!

Any further advice/comments/tips would be definitely appreciated. You are great!!

 

[KristyDarling]

I could''ve written your exact post about 2 1/2 months ago! lol.

My diamond scored a 2.7 (I think) on the HCA. However, it had an AGS grade of 0 (based on the "old" system, the AGS report was from May 04). The pav angle was not within the Tolkowsky ideal range, and I was worried about that. When it scored high-ish on the HCA, I was double-worried. However, all my fears were put to rest when I saw it in person. I compared it side-by-side next to another AGS0 (which had perfect Tolkowsky ideal numbers and presumably, also "excellent" HCA though I didn''t run the numbers), and somehow, mine was brighter and more fiery. My independent appraiser concurred.

Moral of the story -- although the HCA is a great tool for "weeding" if you''re shopping around and pondering multiple stones, the true test is what you see with your eye. If you like it best, then it probably IS best!

 

[aljdewey]

Date: 12/7/2005 4:26:31 PM
Author:jdhunter
Hello, I have purchased an engagement ring (but still have time to return if needed) and compared it to several other rings and I liked it best. It came with a GIA report and a Sarin report. Both suggest that it has an ideal cut. However, when I tested it with the HCA, it came up as a 2.9. I expected it to be much lower and am worried that maybe I am overrrating the brilliance of the stone. Does anyone have advice on the accuracy of this test. I am leaning towards the reality that maybe this is not the ''perfect stone'' that I think it is.

Here is the Sarin information if it helps:

Round Brilliant
D Color
VVS1
1.54 ct
Diameter: 7.43 (7.4-7.45)
Crown Angle: 35
Crown Height: 15
Pavil Angle: 41.1
Pavil Depth: 43.5
Cutlet: 0.3%
Table size: 56
Total Depth: 61.8
4.59mm
Girdle Thickness: 1.1-1.6
Proportion: 0 Ideal

It looks as though it would have qualified as an AGS0 by these numbers under the old AGS system. I don''t know that it would still make the AGS0 under the new system.

The new system tends to look at the relationships between the combinations of crown/pavilion and how that affects light performance. This stone is on the cusp of steep/deep, which may be why it looks a bit dark in the middle. It may have a bit of light leakage under the table.

It''s still likely to be a strong performer compared to most of the run-of-the-mill stuff, but it might not make the top, top grade.

If priced accordingly, could make a nice selection.

 

[Regular Guy]

JD,

Sounds like you''ve already done comparing, and you''re probably fine.

Still don''t know where you are. If you have an independent appraiser nearby, you could probably have one or two options shipped to them at no cost to you, and get an assist to compare, and for $25K, some professional advice from a person who can speak cut intelligently may be worth your while. This one from the price stats list here, for example, would save you $5K, but is really unknown until seen. If you run the search by cut board, you''ll see one or two that are slightly larger than the option you''ve selected, both also from WF, but also run a couple of grand higher, and moreover, WF will not perhaps provide you the same local assistance that the one you found could provide you, and this by itself may worth untold thousands to you, so for this reason alone, too, you could with good reason consider yourself done.

Best of wishes, and sorry for not just telling you to lay down your sword.

 

[jdhunter]

I will definitely take it down to an appraiser to review. I must admit I thought I had this thing nailed by carefully researching optimal cuts, etc.. however, it appears that most of the numbers I was looking at were related to GIA and specifically the Table and Total Depth. I didn''t even know the Pavil and Crown angles were very crucial. I find that many other diamonds I run through the HCA test come out as Excellent, so I am feeling disappointed in my selection. However, I will definitely go down to compare it to other rings prior to making a final decision.

Thanks again for the great help!

 

[Garry H (Cut Nut)]

The new aGS system would bump those proportions.

To everyone doing these comparisons there are 2 other things to consider.

1. you are getting a less spready diamond.
2. the deeper diamond looses more brightness when it gets dirty.

i really need to think up some way to show you guys that.
I have done it in person with Drena''s ear rings at Vegas trade fair and many participants here saw that test and concurred that one very shallow stone was the brightest. when compared to a tolkowsky.

 

[JohnQuixote]

Hey Garry, just keep your diamonds clean and you''ll double your pleasure.

 

[Garry H (Cut Nut)]

Date: 12/7/2005 7:40:42 PM
Author: JohnQuixote
Hey Garry, just keep your diamonds clean and you''ll double your pleasure.

buy shallow diamonds and save 1/2 the effort
Relevant link for Sir John

 

[JohnQuixote]

Date: 12/7/2005 8:01:06 PM
Author: Garry H (Cut Nut)

Date: 12/7/2005 7:40:42 PM
Author: JohnQuixote
Hey Garry, just keep your diamonds clean and you'll double your pleasure.

buy shallow diamonds and save 1/2 the effort
Relevant link for Sir John

Don't think so, mate.

Just like women, non-shallow diamonds are worth the extra effort.

 

[jdhunter]

Hi guys, to sum it up, you agree that (based purely on the numbers) I would probably be able to find a more brilliant sparkly diamond for a similar price? This would seem to confirm what the HCA test showed.

What would you say are the ideal dimensions for maximum brilliance?


Thanks again!!
Jeff

 

[Demelza]

I think you probably have a diamond with a very fine make. Maybe its proportions are not "ideal", but it's unclear whether you (or another layperson) would notice the difference in light performance between your stone and one whose proportions were considered to be more in the "ideal" range. Based on numbers alone, maybe there's a "better" stone out there, but you've actually SEEN this diamond which trumps any and all diagnostic measures out there. On a large purchase such as this, however, I would absolutely take it to an independent appraiser. There are several on PS who have stellar reputations. My personal favorite is Rich Sherwood.

I hope you don't mind me asking you a question, but is there a reason you decided to get a stone with such high color and clarity? Reason I ask is, I just love big diamonds and notice that you have a very healthy budget, so in my mind, I'm thinking you could get a much bigger diamond in the F-G, VS range that would look just as good. But I do respect that for some people size isn't a priority, so feel free to disregard the above.

Good luck and let us know what you decide!

ETA This looks like a really nice stone with more "ideal" proportions. It's quite a bit less expensive because it's an E, VS2. Just a thought.

 

[Garry H (Cut Nut)]

Date: 12/7/2005 11:19:30 PM
Author: jdhunter
Hi guys, to sum it up, you agree that (based purely on the numbers) I would probably be able to find a more brilliant sparkly diamond for a similar price? This would seem to confirm what the HCA test showed.

What would you say are the ideal dimensions for maximum brilliance?


Thanks again!!
Jeff

Jeff there are many many proportions that make for beutiful diamonds.

Ideal-scope images work very well.
And if you stay in the upper red zone of the HCA charts that you can see here http://diamonds.pricescope.com/ideal.asp

 

[aljdewey]

Date: 12/7/2005 7:19:00 PM
Author: Garry H (Cut Nut)
The new aGS system would bump those proportions.

To everyone doing these comparisons there are 2 other things to consider.

1. you are getting a less spready diamond.
2. the deeper diamond looses more brightness when it gets dirty.

i really need to think up some way to show you guys that.

Garry, you have shown us that. It's not that I don't get it......but it's not meaningful to me because I actually clean my diamonds daily. If I planned to walk around with a dirty diamond, maybe I'd find the information more meaningful, but I don't.

As far as spread.......spread's great, but it's not the be-all, end-all. I'd much rather have a bit more fire and a little less spread. So again, while I acknowledge what you're saying is likely true, it doesn't sway me to jump on the shallow bandwagon.

I don't knock your preferences, so if you prefer a shallow diamond, have at it. But one size does not fit all.......so despite your insistent goal to make everyone prefer them, it ain't gonna happen.

 

[valeria101]

Date: 12/8/2005 7:50:47 AM
Author: aljdewey


I don't knock your preferences, so if you prefer a shallow diamond, have at it. But one size does not fit all.......so despite your insistent goal to make everyone prefer them, it ain't gonna happen.

... because those promoting the deeper started first ?

I really don't care how this debate ends, but has anyone given AGS0 a run for the money? The old standard seem to be too easily accepted, IMO. And even then, the HCA was good to keep away from a certain steep-deep 'corner' of the old AGS box. Now they trimmed it in the new system... but if HCA was good basis to criticize the old AGS, why not so for the new...

 

[Garry H (Cut Nut)]

Date: 12/8/2005 7:50:47 AM
Author: aljdewey

Date: 12/7/2005 7:19:00 PM
Author: Garry H (Cut Nut)
The new aGS system would bump those proportions.

To everyone doing these comparisons there are 2 other things to consider.

1. you are getting a less spready diamond.
2. the deeper diamond looses more brightness when it gets dirty.

i really need to think up some way to show you guys that.

Garry, you have shown us that. It''s not that I don''t get it......but it''s not meaningful to me because I actually clean my diamonds daily. If I planned to walk around with a dirty diamond, maybe I''d find the information more meaningful, but I don''t.

As far as spread.......spread''s great, but it''s not the be-all, end-all. I''d much rather have a bit more fire and a little less spread. So again, while I acknowledge what you''re saying is likely true, it doesn''t sway me to jump on the shallow bandwagon.

I don''t knock your preferences, so if you prefer a shallow diamond, have at it. But one size does not fit all.......so despite your insistent goal to make everyone prefer them, it ain''t gonna happen.

Did i say everyone should like what i like Aljd? The chart does not show that

BTW - love the chain saw. You are rather incisive

 

[valeria101]

Garry, could it be that those ranges of proportions work better in a certain type of setting? (e.g shallow in bezels, deep in open settings) etc?