Calling all GIA VG symmetry owners with pics

[belle]

blingergrrl,
here is a chart https://www.pricescope.com/community/threads/ags-and-gia-cut-comparison-charts.41793/ that shows compatible crown/pavilion relationships for each table size. instead of worrying too much about the polish/symmetry grades, focus on finding a crown/pavilion angle that will perform well together. your ''safest'' bets would be the ranges with the blue ''c''. these are angles that get top grades from gia and ags.

 

[E B]

Date: 2/6/2007 6:40:19 PM
Author: Rhino

You mentioned that you're looking at GIA VG's in symmetry, then mention VG's in cut. Did you know it is possible to get a GIA Ex in cut that has VG polish & symmetry if you're looking to shave expense but not at the expense of the optics?

Rhino,

I have a GIA "Excellent" cut with VG polish and VG symmetry, and we paid quite a bit less for it than an EX/EX or ideal (with the same color and quality).

So is it just a matter of finding one due to luck, or is my stone missing even a little something that the ideal stones have (except for perfect symmetry)?

(Forgive me if you've already answered this...there's just so much information!)

 

[blingergrrrl]

Date: 2/6/2007 6:40:19 PM
Author: Rhino

No prob. Glad to be of some help. Let me ask for clarification ms. blingerrrrl.

You mentioned that you're looking at GIA VG's in symmetry, then mention VG's in cut. Did you know it is possible to get a GIA Ex in cut that has VG polish & symmetry if you're looking to shave expense but not at the expense of the optics?

GIA allows 'very good' polish and symmetry in their Ex grade because polish and symmetry grades of VG do not impact the optical properties of brightness, fire and scintillation. Perhaps this is the route you may want to consider. Then again, depending on the budget he may well be able to afford the triple X grade. I'd have to know details which I'm not positive can be discussed here between a consumer and a vendor.

Peace,

Oh, I'm sorry, I wasn't being clear! I had found a diamond that was a GIA VG Cut that also had a VG symmetry and EX polish and scored well below 2.0 on the HCA. I was wondering how much of a difference the VG and EX had on the optical symmetry of the diamond, but now I know the answer is NOT a DARN THING as the symmetry on the certification applies to the physical symmetry (not the OPTICAL symmetry).

I was looking for some optical symmetry in a diamond but not necessarily H&As, but it has to be as much of a fireball as our budget allows. We can easily afford the top of the line 0.5-0.75, but we are wanting to stretch it to the 0.90's (he's pushing for the "magical" 1ct). Honestly, we could afford a SUPERB 1ct diamond, but I just don't know if spending an extra couple of grand ($3000-4000 Canadian) on something that takes up less than 6.5mm on my finger is where we want to spend our money right now (I am SOOOO getting struck down by lightning from the Pricescope Gods!!!).

In summary, we want a gorgeous stone that people will ooohh and aaahh over, but I don't need to stop traffic! (I will save that for the anniversary ring!)...

 

[belle]

Date: 2/6/2007 7:27:13 PM
Author: blingergrrrl

Oh, I''m sorry, I wasn''t being clear! I had found a diamond that was a GIA VG Cut that also had a VG symmetry and EX polish and scored well below 2.0 on the HCA. I was wondering how much of a difference the VG and EX had on the optical symmetry of the diamond, but now I know the answer is NOT a DARN THING as the symmetry on the certification applies to the physical symmetry (not the OPTICAL symmetry).

you got it! you''re absolutely right.

Date: 2/6/2007 7:27:13 PM
Author: blingergrrrl

I was looking for some optical symmetry in a diamond but not necessarily H&As, but it has to be as much of a fireball as our budget allows. We can easily afford the top of the line 0.5-0.75, but we are wanting to stretch it to the 0.90''s (he''s pushing for the ''magical'' 1ct). Honestly, we could afford a SUBERB 1ct diamond, but I just don''t know if spending an extra couple of grand ($3000-4000 Canadian) on something that takes up less than 6.5mm on my finger is where we want to spend our money right now (I am SOOOO getting struck down by lightning from the Pricescope Gods!!!).

In summary, we want a gorgeous stone that people will ooohh and aaahh over, but I don''t need to stop traffic! (I will save that for the anniversary ring!)...

if you get compatible crown/pavilion angles, using the chart i posted, you will get a sparkly diamond.

don''t worry about finding a super douper louper at this point, just look for fine tuning those angles!

you can also save $$ by looking in the lower color/clarity ranges.

 

[blingergrrrl]

Date: 2/6/2007 7:36:31 PM
Author: belle
you got it! you''re absolutely right.

if you get compatible crown/pavilion angles, using the chart i posted, you will get a sparkly diamond.

don''t worry about finding a super douper louper at this point, just look for fine tuning those angles!

you can also save $$ by looking in the lower color/clarity ranges.

Thanks, I bookmarked the page.

 

[Garry H (Cut Nut)]

Rhino it is ridiclous that you use this shallow stone as an example of anything.
Here is some of our communication regarding this stone

I suggest it be read from bottom to top as it is a series of emails:

Good afternoon Garry.

Thoughts below.

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From: Garry Holloway
Sent: Friday, January 12, 2007 5:48 PM
To: 'Jonathan'
Subject: RE: Just completed an article which might interest you

You just demagoged me

I did not say it is too painted

I said it is shallow and painted, which by definition is too painted.

[Rhino] So am I reading you correctly or not? In one sentence you say “I did not say it is too painted then in the next breath you say its shallow and painted, which by definition is too painted”. Apparently you feel it is and I am reading you correctly. Why then accuse me of demagogy if I am reading you correctly? My question still stands. How much painting is too much then with regards to shallow angled diamonds? Please don’t take offense by my question Garry. I don’t claim to know it all but I do have the ability to measure and determine these features and I am familiar with how they impact face up appearance. I don’t see the issue with this diamond being the painting as it’s minimal. I see the issue being the crown/pavilion combination and the diamonds lousy contrast. As indicated via AGS PGS results, the stone lacks contrast and to use Sergey’s term via DiamCalc … too much darkness. That’s all.

You do not understand painting

Painting a shallow stone is a disaster

Painting a slightly deep stone is an advantage

[Rhino] Garry, I’m open to listening. I haven’t seen enough steep angled combos with painting to form an opinion on your last statement but your right on about painting a shallow stone.

AGS agrees with my results as well as GIA

I guess we can all go home and leave it to you?

How come GIA and AGS don’t agree if they both agree with you Jonathon?

[Rhino] What I am pointing out is that in this instance both GIA and AGS agree that this stone does not and would not qualify for top light performance. AGS gives it a sharper hit than GIA does with a grade of 5 in light performance while GIA a VG.

For heavens sake – just find a shallow stone that has excellent synmmetry and is not piqued or painted

Or remove that section

[Rhino] Most diamonds on the market do not have excellent symmetry. Once I find a shallow angled combo like this with Ex symmetry I’ll be sure to include it in the article. This stone represents what is more common on the market place and IMO makes for a good learning stone. The inclusions, while it is an I1 (EGL SI3) are not so large that they impact the optics such as to distort an accurate assessment of its brightness. It is quite easy to see why this diamond doesn’t make GIA or AGS top grade. It does not make AGS 5 because of painting but because of contrast. Painting gets dinged in the AGS system because of dispersion, not contrast although both you and I know that too much painting does have consequences with regards to brightness/contrast.

Garry, bottom line with this. The stone is a commonly cut shallow angled diamond. The HCA rewards it with a score under 2.0. I realize your preference for these and I am not faulting or criticizing you personally for it. Please do not take my commentary personally. I respect your personal preferences. It just happens to be an instance where I side with GIA/AGS on with regards to the analysis of light performance.

Peace,
Jonathan

Kind Regards, Garry Holloway


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From: Jonathan
Sent: Saturday, January 13, 2007 9:27 AM
To: garryh
Subject: RE: Just completed an article which might interest you

Hi Garry,

Just about to head out. A quick question for you below.

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From: Garry Holloway
Sent: Friday, January 12, 2007 5:24 PM
To: 'Jonathan'
Subject: RE: Just completed an article which might interest you

As usual Jonathon there seems little point in logical discussion as you choose to act anyway you wish to make any point you wish.

[Rhino] I don’t think so. It’s ok for us to agree to disagree.

If you wish to compare a shallow painted stone with poor symmetry then find a stone with equally bad symmetry that is over HCA 2 which is easy to find in the market place.

[Rhino] Sure. I see in the other email you’re suggesting this shallow stone is too painted. My question to you Garry is what do you consider *too painted*?

It is very clear that your ‘studies’ are not studies but marketing tools

And that is OK, but do not complain when people treat you as a marketer and not a researcher

[Rhino] While I am a retailer, my studies are not self centered or based on what I think the conclusion should be. Here I think you are greatly mistaken. Why? Because AGS agrees with my results as well as GIA. Garry, understand that my goal in my studies is not marketing but understanding and comprehending the differences between various cut systems. Including yours. I’m not out to bash you or market such and such … When I see a point of contention between your cut grading system and AGS/GIA, my goal is to understand *why* and communicate that, not market something. Catcha tomorrow mate.

Kind regards,

 

[rjdodd]

Date: 2/6/2007 6:50:07 PM
Author: Garry H (Cut Nut)

Date: 2/6/2007 6:07:57 PM
Author: Rhino

Date: 2/6/2007 5:58:01 PM
Author: lumpkin
Rhino, do you happen to have any GIA VG''s that score really well on the HCA? If you could put one of those next to an AGS0 it might be interesting to discuss symmetry vs overall performance. I wish I could remember where but I think there have been threads about really brilliant but not firey, or firey but not brilliant, etc. I know that the AGS0s have both fire and brilliance, but probably not all the GIA EX with EX/EX do. Any examples of those? Just curious.

It''s funny you should ask this. The very first graphic I posted is one I use in my article covering the strengths/limitations to the HCA. It''s a point of contention I have with it as the first graphic I posted is of a diamond that is a GIA Ex/AGS Ideal that gets an HCA of 2.3 (the diamond on the left). The diamond alongside of it gets an HCA of 1.5 and is a GIA VG/AGS 5 because of light performance. Garry has a preference for shallow angled combos that I don''t always share. For me it really depends on the angle combos used. Some shallow angled combos look fine to me but not all of them do. That stone in the first graphic on the right is an example of one and is a good example of a diamond that lacks brightness/contrast/static scintillation yet does have good fire.

As well you know Rhino the stone you used as an example is a very very poor comparison because of many other factors.
Sometimes I am amazed at how ''shallow'' you can be when it comes to your ''research''. (pun intended)

Perhaps you could elaborate here Garry.

To me the stone on the right looks inferior (personal taste obviously) yet gets a better HCA score, what do I need to look out for that the HCA can''t tell me in this situation?

 

[Garry H (Cut Nut)]

Date: 2/6/2007 7:49:37 PM
Author: rjdodd

Perhaps you could elaborate here Garry.

To me the stone on the right looks inferior (personal taste obviously) yet gets a better HCA score, what do I need to look out for that the HCA can''t tell me in this situation?

Because it is inferior.

I posted our communications about it a month ago in a post just above yours.

it is heavily included
has losuy symmetry
is painted which is bad on a shallow stone

And he has done other tricks like holding stones at different angles, cutting and pasting diamonds from one shot into another etc etc.

And this is presented as research.
And I must waste my time defending such tripe.

(can you tell I am cross?)