Table at 59% HELP...

[CRiLLiS]

Any knowledgeable folk out there..?

Here are my stone''s specs:

Crown Depth/Angle...... = 14.5%/35.0
Pavilions Depth/Angle.. = 43.0%/40.8
Girdle = Medium
Culet = None
Polish/Symmetry = Ex/Ex
Cut = Ex (GIA Certified May, 2007)
1.51 F (Very Clean) SI-1

Would this be an AGS 000 Ideal or does the 59% Table make it a 1?
I love the way this stone looks, but I''m a bit stickler on numbers.
Is 59% a good % for table %? Please let me know what you think, Thanks.

 

[Sparkalicious]

Hi Crillis!

I''m so jealous that you find a nice clean SI1 ... I wanted one so badly!

Given that your total depth% is 60 (I didn''t see it listed and just guessed given the crown height + pavillion depth + 2 for the med girdle) the HCA scores 1.9 Excellent overall with VG for Light Rtn, Fire & Scintillation, but EX for Spread of diameter for weight. It falls outside of the AGS Ideal range but within the GIA Excellent range.

From what I understand, the larger table or spread, affects how "fiery" your diamond is ... Instead of showing a spectrum of light, it reflects whiter light when it sparkles? I''m sure someone else would be able to give you a more eloquent or accurate explanation, however, that''s my understanding.

Some people prefer a "shallower" diamond that has a larger spread, as yours does and some prefer a little deeper diamond with a smaller table as they tend to have show more fire.

To me, since the numbers still fall below the HCA 2, the diamond is a decent one and how big the table is etc all boils down to personal preference.

This is just my opinion based on what I have read and understood ... not by any means a pro but I thought I would just chime in to try to help, if possible.

 

[strmrdr]

not my favorite combo.
Id prefer a smaller table or a shallower crown with the 59% table.
I think there are better stones out there.

 

[Hera]

I had a diamond with a 60% table and I was really unimpressed by it. Even though it scored well on the HCA, I personally think it didn''t sparkle as much as the diamond I have now with the smaller table.

 

[Lorelei]

Crillis, if it is a done deal and you can''t or don''t want to return the diamond, then just enjoy it, it looks very nice! If you want an AGS0 then you would need to look again, but although your diamond has a slightly larger table, it still looks to have a very fine cut!

 

[stebbo]

Date: 12/21/2007 1:11:22 AM
Author:CRiLLiS
Would this be an AGS 000 Ideal or does the 59% Table make it a 1?

59% in this combo will be a 1 if nothing else penalizes it. But just. 58% would be in 0 territory.

 

[Garry H (Cut Nut)]

Date: 12/21/2007 11:14:56 AM
Author: stebbo

Date: 12/21/2007 1:11:22 AM
Author:CRiLLiS
Would this be an AGS 000 Ideal or does the 59% Table make it a 1?

59% in this combo will be a 1 if nothing else penalizes it. But just. 58% would be in 0 territory.

Stebbo it would be an AGS 0 quite safely - see the left hand side charts for the latest AGS indications from PGS
http://octonus.com/oct/mss/gia&agspgs.phtml

 

[JohnQuixote]

Stebbo and Garry are both right in the "big picture."

AGSL grades every diamond on its own merits, so it would have to be sent there to know decisively.

Garry's PGS chart predicts 0 in light performance, but implies no inconsistency in angles, no brillianteering issues, perfect wire-frame symmetry and nominal minor facets (a best-case scenario). Meanwhile the official AGSL manufacturer's chart (more conservative) predicts a 1 in light performance.

The actual diamond would have to be sent to the lab to know what precise grade it would receive in light performance but it most likely would be 0 or 1, unless deductions for pretty major inconsistency, brillianteering or minor facet choices were given.

The above regards light performance.

As for the OP's question about "triple 0," again, the only way to know (here with polish/symmetry) is to send it to AGSL, though in practical terms there is no visual difference between VG, EX and Ideal p/s.

 

[Garry H (Cut Nut)]

John the reason that the Cut group and OctoNus do all this work to make these charts is that manufacturers want to know what to do with each piece of rough diamond.

The transperency issue is a huge problem when you are planning the cutting of a diamond.

Having a recomendation chart with a built in "error factor" is pretty useless for a cutter unles he knows the degree and type of fuzziness that has been overlaid on the pure data. AGS have not provided that transperency. Both AGS and GIA want to sell their information systems to each individual machine owned by each cutter - often many machines.

We think that is wrong. It is a miss use of Lab power.

 

[Regular Guy]

Garry, if memory serves, you weren''t fond of this article, either...

 

[JohnQuixote]

Date: 12/21/2007 3:41:20 PM
Author: Garry H (Cut Nut)
John the reason that the Cut group and OctoNus do all this work to make these charts is that manufacturers want to know what to do with each piece of rough diamond.

The transperency issue is a huge problem when you are planning the cutting of a diamond.

Having a recomendation chart with a built in 'error factor' is pretty useless for a cutter unles he knows the degree and type of fuzziness that has been overlaid on the pure data. AGS have not provided that transperency. Both AGS and GIA want to sell their information systems to each individual machine owned by each cutter - often many machines.

We think that is wrong. It is a miss use of Lab power.

This cuts both ways Garry (excuse the pun

). The PGS charts are skewed off-center one way and the AGS guides another. The cut group charts are too generous as some of those combos will not earn 0 unless the diamond is a "perfect" specimen. The AGSL guides are too strict as any deduction is projected out to 1.00 since the lab did not want to give a false impression to manufacturers. We should not forget that these can't be considered grading charts; the actual grading takes far more into account. That's why I'm careful to use the word "predicted" whenever consulting those cut guides, the Cut Group's PGS charts, the records we have been keeping, etc.

In any event, without a scan of this diamond we can only speculate. With a scan we could come up with a PGS score but unless it went to AGS there is no way to know "000" status.

For any who don't know; any diamond's measurements can be plugged into GIA Facetware to get a proportions grade, brillianteering notwithstanding. However the AGS system does not work that way. All 57/58 facets are taken into account via ray tracing. This means one diamond at 59/40.8/35 could be a 0, another could be a 1 and another could possibly be lower. This serves the end-user (the consumer) better than a static chart since each diamond is judged on its own merits - far beyond what a two-dimensional chart or system can take into account.

Garry, I think the AGS system serves this sentiment from the ideal-scope newsletter I received yesterday: "It would be desirable if diamonds became individual and unique again." I do realize the email infers "shape exploration," not necessarily looks within shapes.

Still, don't you think a grading system that adapts itself to each diamond is in the spirit of individuality, even if it's more consumer-friendly than manufacturer-friendly? On that note manufacturers are pretty smart. They figure out what tips a grade one way or another with borderline stones pretty fast, especially if they have the PGS to run themselves (no-brainer)...and this is all to the end-user's benefit, one would hope. The cutters who can't figure it out and/or don't have PGS can simply choose not to do biz with AGSL. Time will tell - if the AGSL system is too cloudy for cutters we will see less stones sent there.

 

[Garry H (Cut Nut)]

Date: 12/21/2007 3:58:05 PM
Author: Regular Guy
Garry, if memory serves, you weren''t fond of this article, either...

I have no problems with the article and its ideas as an approach to grading Ira, other than it is an historic approach - it can be used as the basis of a way to grade a polished damond, but it is difficult to project into the future for the design of new cuts.

It would also be good if AGS could be transperant and issue the same basis of grading for all cuts so that people could truly compare say a round to a princess to a cushion to a....

 

[Garry H (Cut Nut)]

Date: 12/21/2007 4:56:37 PM
Author: JohnQuixote

Date: 12/21/2007 3:41:20 PM
Author: Garry H (Cut Nut)
John the reason that the Cut group and OctoNus do all this work to make these charts is that manufacturers want to know what to do with each piece of rough diamond.

The transperency issue is a huge problem when you are planning the cutting of a diamond.

Having a recomendation chart with a built in ''error factor'' is pretty useless for a cutter unles he knows the degree and type of fuzziness that has been overlaid on the pure data. AGS have not provided that transperency. Both AGS and GIA want to sell their information systems to each individual machine owned by each cutter - often many machines.

We think that is wrong. It is a miss use of Lab power.

This cuts both ways Garry (excuse the pun

). The PGS charts are skewed off-center one way and the AGS guides another. The cut group charts are too generous as some of those combos will not earn 0 unless the diamond is a ''perfect'' specimen. The AGSL guides are too strict as any deduction is projected out to 1.00 since the lab did not want to give a false impression to manufacturers. We should not forget that these can''t be considered grading charts; the actual grading takes far more into account. That''s why I''m careful to use the word ''predicted'' whenever consulting those cut guides, the Cut Group''s PGS charts, the records we have been keeping, etc.

In any event, without a scan of this diamond we can only speculate. With a scan we could come up with a PGS score but unless it went to AGS there is no way to know ''000'' status.

For any who don''t know; any diamond''s measurements can be plugged into GIA Facetware to get a proportions grade, brillianteering notwithstanding. However the AGS system does not work that way. All 57/58 facets are taken into account via ray tracing. This means one diamond at 59/40.8/35 could be a 0, another could be a 1 and another could possibly be lower. This serves the end-user (the consumer) better than a static chart since each diamond is judged on its own merits - far beyond what a two-dimensional chart or system can take into account.

Garry, I think the AGS system serves this sentiment from the ideal-scope newsletter I received yesterday: ''It would be desirable if diamonds became individual and unique again.'' I do realize the email infers ''shape exploration,'' not necessarily looks within shapes.

Still, don''t you think a grading system that adapts itself to each diamond is in the spirit of individuality, even if it''s more consumer-friendly than manufacturer-friendly? On that note manufacturers are pretty smart. They figure out what tips a grade one way or another with borderline stones pretty fast, especially if they have the PGS to run themselves (no-brainer)...and this is all to the end-user''s benefit, one would hope. The cutters who can''t figure it out and/or don''t have PGS can simply choose not to do biz with AGSL. Time will tell - if the AGSL system is too cloudy for cutters we will see less stones sent there.

Well considered thoughts as usual John.

I think it is better for cutters to know "perfect" data and then they can decide for themselves what "less than perfect" sym and to what extent NQR etc will effect a stones grade. Of course we know for example that a tilted table causes very bad numeric grading, but has little or no effect on PGS type 3D light performance approach of AGS, where as it could throw off their ideal symmetry grade. So there is and will always be problems with rule based grading methods.
Hard to find the perfect solutions.

 

[JohnQuixote]

Date: 12/21/2007 5:53:15 PM
Author: Garry H (Cut Nut)

Well considered thoughts as usual John.

I think it is better for cutters to know 'perfect' data and then they can decide for themselves what 'less than perfect' sym and to what extent NQR etc will effect a stones grade. Of course we know for example that a tilted table causes very bad numeric grading, but has little or no effect on PGS type 3D light performance approach of AGS, where as it could throw off their ideal symmetry grade. So there is and will always be problems with rule based grading methods.
Hard to find the perfect solutions.

You said it.

Your point is good. In practice it's easier for a cutter to consult GIA's tables, knowing if the (rounded) 2D measurements are there they'll get the grade pending brill & E/VG finish. Predicting AGSL results is not nearly as simple but the good news is that the red zone on those cutting guides is pretty inviolable (you'd have to muck something up pretty badly to fall from 0 LP with major #s in that area). Borderline combos are trickier and then you always have their highly aggressive p/s judgments to consider.

As our moms always said (that's mum to you, Garry?) "No one said it would be easy, honey."

 

[Garry H (Cut Nut)]

Date: 12/21/2007 6:41:14 PM
Author: JohnQuixote



As our moms always said (that''s mum to you, Garry?) ''No one said it would be easy, honey.'' darling, darlin'', sweetheart, possum etc, but never ever honeee Johneee

 

[JohnQuixote]

Possum???

 

[Garry H (Cut Nut)]

Date: 12/21/2007 7:40:08 PM
Author: JohnQuixote

Possum???

Not sure if Barry humphrey''s started it, or if he just picked up on what was already there
http://www.google.com.au/search?sourceid=navclient&ie=UTF-8&rls=GGLL,GGLL:2007-51,GGLL:en&q=Hello+Possums+Dame+Edna

 

[CRiLLiS]

I have to say I was a bit bummed after inputting the specs into the HCA Evaluator. (VG VG VG EX = 1.9 - EX Visual Performance & within TIC range) ...not because it''s horrendous, but because I would have loved Ex across the board. I know I''m not thrilled with the 59% table size, but perhaps it is because of the ideal "on paper" parameters and the stigma of tables above 57%. Honestly, in person this piece looks fantastic and apart from my technical issue with the aforementioned I have to say it is a very clean diamond for its grade.

I very much appreciate everyone''s responses; diamond shopping is definately a difficult task for spec sticklers like myself.

FYI: I didn''t purchase this piece over the internet, I actually sat down in a 6x6 room and hand picked it out from (9 - ExExEx Gia diamonds ranging from D-I, 1.35-1.71) and (1 - AGS 000 1.53 H), this one just kept popping out at me.

Thanks Again!!!

 

[Garry H (Cut Nut)]

Date: 12/21/2007 10:41:58 PM
Author: CRiLLiS
I have to say I was a bit bummed after inputting the specs into the HCA Evaluator. (VG VG VG EX = 1.9 - EX Visual Performance & within TIC range) ...not because it''s horrendous, but because I would have loved Ex across the board. I know I''m not thrilled with the 59% table size, but perhaps it is because of the ideal ''on paper'' parameters and the stigma of tables above 57%. Honestly, in person this piece looks fantastic and apart from my technical issue with the aforementioned I have to say it is a very clean diamond for its grade.

I very much appreciate everyone''s responses; diamond shopping is definately a difficult task for spec sticklers like myself.

FYI: I didn''t purchase this piece over the internet, I actually sat down in a 6x6 room and hand picked it out from (9 - ExExEx Gia diamonds ranging from D-I, 1.35-1.71) and (1 - AGS 000 1.53 H), this one just kept popping out at me.

Thanks Again!!!

Absolutely a perfect way tochoose Crillis

It should be a very bright stone, and in that environment, it would probably have been shouting Me me Me at you

 

[stebbo]

Date: 12/21/2007 5:53:15 PM
Author: Garry H (Cut Nut)

I think it is better for cutters to know 'perfect' data and then they can decide for themselves what 'less than perfect' sym and to what extent NQR etc will effect a stones grade.

Hmmm, it's mind-boggling to even think of a real-time scanner directing a computer-controlled cutter via PGS's algorithm let alone a manufacturer taking an educated guess at the effect.

There are guidelined 4's sitting in the PGS 0 box for Crillis' stone--scary.

I'd guess Octonus will be incorporating (if not already) their PGS generated results into their rough planning software - it'll be interesting to see how many end up as 0's in practice compared to the cutting guidelines, and is it worthwhile expanding the range.

PS. Thanks for link to the PGS charts - very interesting. I note that they don't seem to differentiate diameter like the guidelines do.

 

[CRiLLiS]

Wow...so many different charts out there that it''s hard to determine. Some say "0" some say "1", I guess it really boils down to what looks good at this point.

 

[stebbo]

Date: 12/23/2007 9:20:53 PM
Author: CRiLLiS
Wow...so many different charts out there that it''s hard to determine. Some say ''0'' some say ''1'', I guess it really boils down to what looks good at this point.

Don''t worry about all this geeky stuff. Sorry for stealing the thread a bit, but it opened up a good topic.

Garry and John summed it up with your eyes being the perfect way to choose and you''ll never know if what grade it will be unless you send it there.

 

[JohnQuixote]

Date: 12/22/2007 11:09:20 PM
Author: stebbo


I'd guess Octonus will be incorporating (if not already) their PGS generated results into their rough planning software - it'll be interesting to see how many end up as 0's in practice compared to the cutting guidelines, and is it worthwhile expanding the range.

Agreed. The borderline combos we have seen can go one way or the other. Much of it depends on cut consistency. This is not surprising, considering that good optical symmetry results in more crisp contrast; in even the basic ASET view you can see how well defined the edges of intense light return versus obstruction are.

I do sympathize with the point that this is a headache for cutters to figure out pre-lab - the upstream guys should be able to know how it's going to come out (important deci$ion$) - but at the same time this has really caused some top cutters to re-examine what they are doing.

CRiLLiS, nevermind us.

We discuss and debate shades of white, even.

 

[Lynn B]

Crillis,

Believe me, you have entered the Numbers Danger Zone here! Haha!

Seriously, like John said, we labor and belabor, anguish and agonize, split frog hairs and then split them again. But the bottom line is, you saw this diamond, you compared it to others, and it *spoke* to you. That's ultimately the best and final test... what your eyes see. Remember, you will wear the diamond, not the paper.

I bet it is a gorgeous stone.

Enjoy!

 

[Garry H (Cut Nut)]

Date: 12/24/2007 4:58:16 PM
Author: Lynn B
Crillis,

Believe me, you have entered the Numbers Danger Zone here! Haha!

Seriously, like John said, we labor and belabor, anguish and agonize, split frog hairs and then split them again. But the bottom line is, you saw this diamond, you compared it to others, and it *spoke* to you. That''s ultimately the best and final test... what your eyes see. Remember, you will wear the diamond, not the paper.

I bet it is a gorgeous stone.

Enjoy!

Lynn no one has yet managed to split a frog''s hair. i am sure, I did a lot of research on it

 

[CRiLLiS]

Date: 12/24/2007 11:10:16 PM
Author: Garry H (Cut Nut)

Date: 12/24/2007 4:58:16 PM

Author: Lynn B

Crillis,


Believe me, you have entered the Numbers Danger Zone here! Haha!

Seriously, like John said, we labor and belabor, anguish and agonize, split frog hairs and then split them again. But the bottom line is, you saw this diamond, you compared it to others, and it *spoke* to you. That''s ultimately the best and final test... what your eyes see. Remember, you will wear the diamond, not the paper.


I bet it is a gorgeous stone.

Enjoy!

Lynn no one has yet managed to split a frog''s hair. i am sure, I did a lot of research on it

...If the frog were a prince or princess, I''m sure he or she had split hairs.

I really enjoy reading these debates.

Thanks guys/gals...Happy Holidays!!!

 

[Lynn B]

Date: 12/24/2007 11:10:16 PM
Author: Garry H (Cut Nut)

Lynn no one has yet managed to split a frog''s hair. i am sure, I did a lot of research on it

Garry, you scalawag!

I''m beginning to think you''re following me around just to give me a hard time!!!