GIA Very Good Cut diamond scoring 1.8 on HCA?

[Natylad]

Hello to my fellow Pricescopers
I recently bought a GIA certified diamond, which is graded as follows:
Cut grade: Very Good
Polish: Excellent
Symmetry: Very Good
I put the numbers in the HCA tool and the results were:
Light return: Very Good
Fire: Excellent
Scintillation: Very Good
Spread: Excellent
Total Visual Performance: 1.8 Excellent within TIC range.
Now, after having spent many years educating myself on PS, I know that there are many GIA triple excellent diamonds which don't score under 2 on the HCA and in fact are not excellent performers. But I admit that i wasn't aware of the fact that a diamond graded Very Good in cut by GIA could score 1.8 on the HCA.
I have the diamond in my hands right now and I have checked it in different light conditions and it seems to perform wonderfully but obviously I'm not an expert.
Do you guys think that regardless of the fact that the diamond is not considered an "ideal cut" by GIA, its excellent score on HCA is enough proof that it's an excellent performer? (I wouldn't have bought a diamond graded less than excellent in cut but i decided to get this one, because I checked it on HCA BEFORE buying it and it scored that well. Nevertheless, I will use this diamond for a ring, which I will be able to look at all day long and I'd like to make sure that I made the right choice).
Thank you in advance!

 

[gm89uk]

If you could share the GIA diamond certificate / photos / video / idealscope /ASET anything you have.

 

[bmfang]

I wouldn't purchase a stone solely based off a HCA score. The tool is only supposed to be a filter rather than a selection tool. Though the grading report for this stone would be an interesting one to look at. If the stone actually has decent proportions and looks good, that's really the main selection tool.

 

[flyingpig]

It is possible to find a good looking GIA VG cut stone.
It all depends on the reason for deduction.
girdle thickness, girdle thickness variation (painting/digging), proportions, culet, etc...

 

[ChristineRose]

The HCA only takes into account five of the hundreds of numbers it takes to fully describe a diamond. This diamond probably was dinged on something else-girdle, symmetry, any or all of the minor facets. GIA trumps the HCA on this one as they got to look at the whole diamond. I would keep looking.

 

[Garry H (Cut Nut)]

If you share the numbers we can probably ID the issue.
But it may be that GIA thinks it is too shallow and I don't

 

[Danakramer]

I have a similar story. I bought a 1.01 round, J color , SI1 on ebay a couple years ago. It's a GIA, vg,vg,excellent. The table is 58% ,depth 59.7%,33% crown,41% pavillion. I bought it because the HCA was under 2 ( and the price was good) All I can tell you is the stone is an absolute killer.
Couple of weeks ago I bought a 1.04 round ,J color, vvs2 GIA ,exc,exc,exc, which also scored below 2 on the HCA, that stone is also fantastic but not better then that first stone I mentioned.

 

[Garry H (Cut Nut)]

I have a similar story. I bought a 1.01 round, J color , SI1 on ebay a couple years ago. It's a GIA, vg,vg,excellent. The table is 58% ,depth 59.7%,33% crown,41% pavillion. I bought it because the HCA was under 2 ( and the price was good) All I can tell you is the stone is an absolute killer.
Couple of weeks ago I bought a 1.04 round ,J color, vvs2 GIA ,exc,exc,exc, which also scored below 2 on the HCA, that stone is also fantastic but not better then that first stone I mentioned.

In that case probably the girdle is very thin

 

[WinkHPD]

I would note that GIA’s EX grade is centered deeper than many other systems, including HCA. Here is a quote from John Pollard explaining how systems differ. I would also note that GIA’s grade is also far wider, allowing many diamonds that will be rejected by specialists who focus on top performance.

<< In the most popular metrics discussed here: AGSL, GIA, HCA and AGA - average pavilion angles from 40.6 - 41.0 have the greatest approval cross-system. There are exceptions but that range is highly considered the safe-zone according to those metrics, as well as the consensus of the most high-achieving diamond cutters and research gemologists I know. For the record, the AGSL shows most 0 light performance candidates to be in that range. The HCA and AGA prefer the shallow side of that range (and a bit lower). GIA prefers the steeper side of that range (and a bit higher). This is why the GIA gives EX to steep diamonds the HCA rejects and the HCA gives thumbs-up to shallow diamonds the GIA system doesn't reward.>>

The full discussion is here:

https://www.pricescope.com/community/threads/help-gia-excellent-cut-vs-hca.177583/#post-3232643

Wink

 

[Natylad]

Thank you all so much for the answers. The diamond's performance is excellent to my eyes, even in comparison to my GIA certified, triple Ex, Hearts and Arrows stone of my engagement ring (the H&A cut of the diamond was certified by an independent appraiser).
I will now share the numbers of the diamond discussed in this thread, which i have already decided to keep and use for a right hand ring project:

Table: 61%
Depth: 59.1%
Crown angle: 32.5
Pavilion angle: 40.8
Culet: None
Girdle: medium to slightly thick

Thanks again for all your help and valuable information. I really appreciate it.

 

[flyingpig]

My family owns a diamond with the nearly exact proportion combo (I think it is even shallower at 32/40.8/61). It is a good looking stone, though a bit flat.

 

[ChristineRose]

It's shallow. More mirror, less prism, but entirely a matter of taste. Your taste is more like Gary Holloway's and less like the test groups the GIA surveyed.

Here's a GIA publication that you can use to look up the GIA grades. These grades assume there's nothing else amiss with the diamond and are similar to the HCA.

http://diamondcut.gia.edu/pdf/booklet_cut_estimation_tables_highres.pdf

 

[AGBF]

This is a complicated topic and you have selectively chosen to give only partial information and no images so the actual appearance of your diamond us unknown to all the posters here. In that respect I doubt you received any applicable advice to your specific diamond that allowed you to answer your initial question(s).

Natylad-

I usually spend my time in Hangout nowadays, but on a whim I stopped by here tonight. I am very glad I did because doing so allowed me to see the egregious error you had made when asking for advice here in RockyTalky. You really should have posted more information when you asked for help with your diamond. It was quite inconsiderate of you to expect experts here to give their valuable time to you when you did not make more of an effort to give them the information they needed to render their judgement(s). I hope that in the future you will be more thoughtful. Pricescope has needs, you know. Its running smoothly is dependent upon everyone working together and pulling his weight.

Your friend,
Deb

 

[Natylad]

The lighting you use to compare diamonds in makes a huge difference. Use a lot of spot lighting sources you will be better able to compare fire. Use lower diffuse lighting conditions you will be better able to compare brightness.

This is a complicated topic and you have selectively chosen to give only partial information and no images so the actual appearance of your diamond us unknown to all the posters here. In that respect I doubt you received any applicable advice to your specific diamond that allowed you to answer your initial question(s).

However based on http://diamondcut.gia.edu/pdf/booklet_cut_estimation_tables_highres.pdf

A CA32.5/OA40.8/T61% would receive a cut grade of VG by GIAL on that combination alone, as it is just outside the border of their Excellent cut grade.

On the more subjective side you have already validated your purchase anyway and made your decision, so best of luck and enjoy your diamonds I am sure they are beautiful.

Dear gretag:
I haven't "selectively chosen to give only partial information and no images". The information that I gave is the only information that I have. I bought the stone through Blue Nile UK and the website didn't offer any photos or additional info on the diamond, only the numbers from the GIA report.
Furthermore, given the fact that i didn't have any photos of the stone to post here, you are correct when you say that "the actual appearence of my stone is unknown to all the posters here" but since you are very new in this forum and i am a very old member, i will kindly give you a piece of advice: Get used to it, because this is what we usually do around here! We discuss diamonds that we haven't seen and the actual appearence of which is unknown to us while we're discussing them!
Last but not least, contrary to what you obviously think, many of the answers given to me in this thread, especially from long time members of the forum, have answered some of my initial questions and I'm sure have helped other members who might have similar questions.

Natylad-

I usually spend my time in Hangout nowadays, but on a whim I stopped by here tonight. I am very glad I did because doing so allowed me to see the egregious error you had made when asking for advice here in RockyTalky. You really should have posted more information when you asked for help with your diamond. It was quite inconsiderate of you to expect experts here to give their valuable time to you when you did not make more of an effort to give them the information they needed to render their judgement(s). I hope that in the future you will be more thoughtful. Pricescope has needs, you know. Its running smoothly is dependent upon everyone working together and pulling his weight.

Your friend,
Deb

 

[bmfang]

sometimes bn blind purchases can work out well in the end.

 

[AprilBaby]

Don't know who you are but you are being rough. Take it easy.

 

[Natylad]

Speak for yourself, not all of pricescope wants to spin the hamster wheel and guess with incomplete information. After 8 years here I am sure you know where to buy an Idealscope or ASET scope and how to take a few pictures. As you should already know HCA is a rejection system <2.0 candidates could be fine(or not) and the next step is to confirm with an Idealscope image.



You may have 2000+ posts dating back to 2009 but you still haven't figured out that an appraiser who took a GIA course cannot certify any diamonds as H&A. In fact GIA-GTL doesn't certify diamonds as H&A. GIA grades diamonds and they provide grading reports not certifications and they most certainly don't grade hearts and arrows.

If all you wanted to do was romance your stone and let everyone know that some GIA VG get <2.0 in HCA and that they are "good enough" you could have saved everybody the charade. In any case this diamond is NOT a top performer no matter how beautiful you think it is and that is a fact even if some rejection systems would accept it as "good enough".

If all you wanted was praise and validation for your purchase decision you can post pictures in Show me the Bling and everyone will tell you "wow sparkly beautiful" so you can have that warm fuzzy feeling. I personally hate placebo but to each their own.

I really feel sorry for the people who have to deal with you in real life

 

[PintoBean]

Speak for yourself, not all of pricescope wants to spin the hamster wheel and guess with incomplete information. After 8 years here I am sure you know where to buy an Idealscope or ASET scope and how to take a few pictures. As you should already know HCA is a rejection system <2.0 candidates could be fine(or not) and the next step is to confirm with an Idealscope image.



You may have 2000+ posts dating back to 2009 but you still haven't figured out that an appraiser who took a GIA course cannot certify any diamonds as H&A. In fact GIA-GTL doesn't certify diamonds as H&A. GIA grades diamonds and they provide grading reports not certifications and they most certainly don't grade hearts and arrows.

If all you wanted to do was romance your stone and let everyone know that some GIA VG get <2.0 in HCA and that they are "good enough" you could have saved everybody the charade. In any case this diamond is NOT a top performer no matter how beautiful you think it is and that is a fact even if some rejection systems would accept it as "good enough".

If all you wanted was praise and validation for your purchase decision you can post pictures in Show me the Bling and everyone will tell you "wow sparkly beautiful" so you can have that warm fuzzy feeling. I personally hate placebo but to each their own.

I'm trying to read this with all kinds of cartoon voices in my head but the tone is still coming across a bit hostile and aggressive.

I have all kinds of diamonds that are all over the board from very good to super star performers. I am thankful that as each day goes by, my failing eyesight and my sieve brain make my diamonds more eye clean and more mind clean.

Oh, and let me introduce myself to you - Hello @gretag, I'm Pintobean. . Please don't re-fry me as we approach cinco de mayo.

 

[AGBF]

Speak for yourself, not all of pricescope wants to spin the hamster wheel and guess with incomplete information.

Actually, hamster wheels do not tell anyone the answer to questions. With the way you reason, it doesn't matter how much information you are given or how good its quality, you will still come to a nonsensical conclusion. You should stop giving advice.

AGBF

 

[Karl_K]

gretag is a troll who has been banned multiple times, ignoring him until the admin can ban him once again is the best thing to do.

Natylad,
Sorry for the rough treatment, it is not what PS should be about!

 

[AGBF]

gretag is a troll who has been banned multiple times, ignoring him until the admin can ban him once again is the best thing to do.

Natylad,
Sorry for the rough treatment, it is not what PS should be about!

Thank you for the information, Karl. I will take your advice now that I know!

 

[MJ_Mac]

gretag is a troll who has been banned multiple times, ignoring him until the admin can ban him once again is the best thing to do.

Natylad,
Sorry for the rough treatment, it is not what PS should be about!

Karl K - I know this happens from time to time, but how do you know it's the same person? I know Ella has mentioned one troll that pops up everyone once in a while. I was suspecting this person was a troll judging by their response to people's queries. Is it the writing style that gives them away? I was able to identify to Ella a while back about 4 posters that were trolls (or maybe in this case it was spam because they were harmless just taking up room). In this case I assume it was the same person with 4 different identities. Sorry for being long winded - not enough coffee this morning (lol). I'm just wondering what to look for besides the excessive rudeness.

Edited to add: Natylad, sorry to threadjack!

 

[Karl_K]

Poodle4me,
Patterns.
A poster will always revert to the same pattern even if they try very hard to hide it.
I have a very strong pattern for example, so if I posted under another name someone who has read even a few of my my posts will quickly pick it up.
Some are harder to pick up than others but everyone has a pattern.
It is like a voice.

 

[MJ_Mac]

Poodle4me,
Patterns.
A poster will always revert to the same pattern even if they try very hard to hide it.
I have a very strong pattern for example, so if I posted under another name someone who has read even a few of my my posts will quickly pick it up.
Some are harder to pick up than others but everyone has a pattern.
It is like a voice.

Thanks Karl - that makes a lot of sense.

 

[Natylad]

I'd like to thank Karl K and all the other members for their response to this issue. After the first shock, I realised myself that this must have been a troll.
Thanks to everybody for making this community a great place to make friends, get excellent advice and help and share our common bling interests.

 

[flyingpig]

The best strategy is to hit that report concern button to notify the admin of "troll/banned member" and ignore. Attention is what these people want.

 

[gm89uk]

Congratulations on your diamond!

 

[Danakramer]

In that case probably the girdle is very thin

You're absolutely right, the girdle is listed as very thin on the GIA Cert (13359233) I had two people look at that stone after I bought it ( one was a GG ) neither said a word about the girdle thickness, or lack of it.