Anyway to quantify how much ''BIGGER'' Exellent Cut Diamonds Look Compared to Fair Cut?

[wolfelot]

I recently purchased a round GIA Lab, Excellent Cut, 1.01 ct, SI2 (100% eye clean, cloud did not make the grade), E color, and 1.3 on the HCA from James Allen. I am super, super happy with the diamond. Thank you so much to Pricescope on helping me to make an informed buying decision! There is so much information here!

Throughout my research I kept seeing where people would say that an excellent cut GIA or AGS 000 diamond will actually look like a larger stone than the same sized stone all other things equal when the diamond is only fair or good cut. For instance, I read discussions where people who had a .75 ct Excellent cut diamond in their ring would say that people would ask or assume that their diamond was over 1.0 carat because it looked so brilliant/big. I realize that spread can play a role in this because if a diamond is too deep it will look small for its size and if it is too shallow it will look bigger in some ways but will suffer in others.

Is there anyway to quantify how much ‘bigger’ a GIA excellent cut would look compared to a GIA fair cut?

What are your thoughts?

 

[stone-cold11]

No, because it depends on individual proportions of what result in the ideal cut and the fair cut.

 

[Rockdiamond]

People say a lot of things- not all match with facts.
There is no truth whatsoever in the assumption that every GIA EX cut grade will look larger than every stone given a grade of "Fair"- although it's virtually unheard of to find a stone with a cut grade of "fair" as the cutters know when they've got a really badly cut stone and will either submit to EGL ( or another non GIA lab), or try to sell without a report.

There are many cases of stones with VG cut grade looking larger than stones of identical weight given EX cut grade.

 

[WinkHPD]

Date: 6/29/2010 4:16:15 PM
Author: Rockdiamond
People say a lot of things- not all match with facts.
There is no truth whatsoever in the assumption that every GIA EX cut grade will look larger than every stone given a grade of ''Fair''- although it''s virtually unheard of to find a stone with a cut grade of ''fair'' as the cutters know when they''ve got a really badly cut stone and will either submit to EGL ( or another non GIA lab), or try to sell without a report.

There are many cases of stones with VG cut grade looking larger than stones of identical weight given EX cut grade.

I bet there are Many Many more cases of stones with Ex cut grades that look bigger than stones with fair cut grades of identicle weight. It is that edge to edge sparkle.

I will admit that you might find some that are the way you state it, but I would need to see them to see if I could understand why, when it is normally the Ex looking bigger than the fair. Of course GIA allows steep deeps in their Ex range, so I am going to guess that it might be a fair with a more proper spread against a GIA steep deep EX that you are talking about.

All of which boils back down to the FACT that the paper only tells us so much, the images only tell us so much, and they both help us weed out the obvious loosers, but the eye is the final arbitor of what the eye likes. Baskins and Robbins thrive on the FACT that many tongues like many flavors, just as our clients are free to like many different looks.

Still, I think that while not every GIA Ex will look larger than every fair, I think that there is a LOT of truth in the FACT that most EX stones will look larger than most identical weight Fair stones. Put those GIA Fair stones against AGS 0 cut stones and the Truth will be even more evident. I would bet that it would be extremely few, if any GIA Fair stones, that would have the edge to edge sparkle to actually look bigger than an AGS 0 cut diamond of the same weight. Obviously a round brilliant so shallow that it should be called a pancake cut might look bigger, but it would certainly not have the sparkle to make it look nicer.

Wink

 

[yssie]

Date: 6/29/2010 3:58:30 PM
Author:wolfelot

Throughout my research I kept seeing where people would say that an excellent cut GIA or AGS 000 diamond will actually look like a larger stone than the same sized stone all other things equal when the diamond is only fair or good cut. For instance, I read discussions where people who had a .75 ct Excellent cut diamond in their ring would say that people would ask or assume that their diamond was over 1.0 carat because it looked so brilliant/big. I realize that spread can play a role in this because if a diamond is too deep it will look small for its size and if it is too shallow it will look bigger in some ways but will suffer in others.

Is there anyway to quantify how much ‘bigger’ a GIA excellent cut would look compared to a GIA fair cut?

What are your thoughts?

I can see how someone new to diamonds might come onto this forum and leave thinking the ideal diamond is like a white mini-LED with a permanent lens over it that glows in the dark..

Unfortunately that's not really the case

So a 0.75 will look like a 0.75, a J will look like an I/J/K, and an ideal w/o fluor won't glow in the dark. It's just that people who haven't seen nicely cut diamonds don't really have any concept of how a well-cut 0.75 J should look and perform

So no, having a well-cut stone isn't really an illusion of anything, it just always comes out favourably in comparison to a poorly cut stone. And there's no metric or consistent proportion since there's such a variety of parametres accepted into each report grade

So glad you're thrilled with your stone wolfelot!

 

[Rockdiamond]

Wink- I have not personally seen any stones graded "Fair" that I can recall.
But I have seen many cases of stones of EX and VG cut grade that were "spready"....having a larger appearance than stones of the same weight that would be deemed "better cut" by many people on PS.

 

[wolfelot]

Your responses were pretty much what I had figured. An Excellent cut or AGS 0 diamond will generally show more favorably than a Fair cut diamond of the same weight. There also isn''t any metric to quantify it. You just have to look. I didn''t really feel like Excellent Cuts looked much BIGGER but they looked BETTER than fair cuts when I was doing the in-person comparisons.

 

[Isabelle]

Date: 6/29/2010 4:16:15 PM
Author: Rockdiamond
People say a lot of things- not all match with facts.

There is no truth whatsoever in the assumption that every GIA EX cut grade will look larger than every stone given a grade of ''Fair''- although it''s virtually unheard of to find a stone with a cut grade of ''fair'' as the cutters know when they''ve got a really badly cut stone and will either submit to EGL ( or another non GIA lab), or try to sell without a report.


There are many cases of stones with VG cut grade looking larger than stones of identical weight given EX cut grade.

This is so true.

 

[Isabelle]

Date: 6/29/2010 5:08:44 PM
Author: yssie

I can see how someone new to diamonds might come onto this forum and leave thinking the ideal diamond is like a white mini-LED with a permanent lens over it that glows in the dark..


Unfortunately that''s not really the case

So a 0.75 will look like a 0.75, a J will look like an I/J/K, and an ideal w/o fluor won''t glow in the dark. It''s just that people who haven''t seen nicely cut diamonds don''t really have any concept of how a well-cut 0.75 J should look and perform

This will shock you but I 100% agree with you!

 

[yssie]

Date: 6/29/2010 7:23:35 PM
Author: Isabelle

Date: 6/29/2010 5:08:44 PM
Author: yssie

I can see how someone new to diamonds might come onto this forum and leave thinking the ideal diamond is like a white mini-LED with a permanent lens over it that glows in the dark..


Unfortunately that''s not really the case

So a 0.75 will look like a 0.75, a J will look like an I/J/K, and an ideal w/o fluor won''t glow in the dark. It''s just that people who haven''t seen nicely cut diamonds don''t really have any concept of how a well-cut 0.75 J should look and perform

This will shock you but I 100% agree with you!

hehe

 

[Dancing Fire]

Date: 6/29/2010 4:34:26 PM
Author: Wink

Still, I think that while not every GIA Ex will look larger than every fair, I think that there is a LOT of truth in the FACT that most EX stones will look larger than most identical weight Fair stones. Put those GIA Fair stones against AGS 0 cut stones and the Truth will be even more evident. I would bet that it would be extremely few, if any GIA Fair stones, that would have the edge to edge sparkle to actually look bigger than an AGS 0 cut diamond of the same weight. Obviously a round brilliant so shallow that it should be called a pancake cut might look bigger, but it would certainly not have the sparkle to make it look nicer.

Wink

yeah,i had one those 60/60 pancake cut with no crown height.

 

[Garry H (Cut Nut)]

Date: 6/29/2010 3:58:30 PM
Author:wolfelot

I recently purchased a round GIA Lab, Excellent Cut, 1.01 ct, SI2 (100% eye clean, cloud did not make the grade), E color, and 1.3 on the HCA from James Allen. I am super, super happy with the diamond. Thank you so much to Pricescope on helping me to make an informed buying decision! There is so much information here!

Throughout my research I kept seeing where people would say that an excellent cut GIA or AGS 000 diamond will actually look like a larger stone than the same sized stone all other things equal when the diamond is only fair or good cut. For instance, I read discussions where people who had a .75 ct Excellent cut diamond in their ring would say that people would ask or assume that their diamond was over 1.0 carat because it looked so brilliant/big. I realize that spread can play a role in this because if a diamond is too deep it will look small for its size and if it is too shallow it will look bigger in some ways but will suffer in others.

Is there anyway to quantify how much ‘bigger’ a GIA excellent cut would look compared to a GIA fair cut?


What are your thoughts?

This shows what you are discussing - 2 1ct equivalent CZ''s - one exceptional cut and one a real dog. When you hold them under a counter out of the light - you would swear the bad stone is 1/2 the diameter as shown on this 1.5 minute video

 

[Rockdiamond]

Not to say there are not "fair" cut grade stones out there- surely there are plenty of stones GIA would grade "Fair" cut grade, if such stones were submitted.
Part of my point is that such stones are virtually never submitted to GIA- therefore "Fair" cut graded diamonds are pretty much impossible to find.
There are plenty of VG cut grade stones on the market- many of which will have a larger face up than other stones graded EX cut grade by GIA.

If we did compare a well cut 60/60 to a more traditional Tolkowski 56 table 61 depth stone, many times the 60/60 appears larger- even if the measurements are the same.
Once we can upload photos again, I have some photos to show what I''m talking about.

 

[wolfelot]

Date: 6/29/2010 8:28:45 PM
Author: Garry H (Cut Nut)

Date: 6/29/2010 3:58:30 PM

Author:wolfelot

I recently purchased a round GIA Lab, Excellent Cut, 1.01 ct, SI2 (100% eye clean, cloud did not make the grade), E color, and 1.3 on the HCA from James Allen. I am super, super happy with the diamond. Thank you so much to Pricescope on helping me to make an informed buying decision! There is so much information here!

Throughout my research I kept seeing where people would say that an excellent cut GIA or AGS 000 diamond will actually look like a larger stone than the same sized stone all other things equal when the diamond is only fair or good cut. For instance, I read discussions where people who had a .75 ct Excellent cut diamond in their ring would say that people would ask or assume that their diamond was over 1.0 carat because it looked so brilliant/big. I realize that spread can play a role in this because if a diamond is too deep it will look small for its size and if it is too shallow it will look bigger in some ways but will suffer in others.

Is there anyway to quantify how much ‘bigger’ a GIA excellent cut would look compared to a GIA fair cut?



What are your thoughts?

This shows what you are discussing - 2 1ct equivalent CZ''s - one exceptional cut and one a real dog. When you hold them under a counter out of the light - you would swear the bad stone is 1/2 the diameter as shown on this 1.5 minute video

YES Garry! That was exactly what I was referring to. In the video you could really see what appeared to be a difference in size/diameter despite just a 4% difference in diamond weight. When I was looking at diamonds at the store it was apparent to me they were pretty much the same because I was closely inspecting them and could see they were about the same size. However, the better cut stone looked much BETTER. If I was a casual observer of those stones on someone''s ring out in public, I would generally think the better cut diamond was quite a bit larger in size.

I thought of this topic because today I saw on some mainstream B&M websites some very low quality prefab rings for less than what I paid except they were 2.0 ct, J-k, I2s that didn''t even have ''cut'' mentioned in the description nor a reference to a certification. I figured that those diamonds will often be ugly yellow stones that will ''appear'' considerably smaller than a truly excellent cut diamond of the same carat size. BTW I''m very glad I didn''t even look at those websites when I was shopping. I was pretty appalled.

 

[Isabelle]

Date: 6/29/2010 8:21:56 PM
Author: Dancing Fire

Date: 6/29/2010 4:34:26 PM

Author: Wink



Still, I think that while not every GIA Ex will look larger than every fair, I think that there is a LOT of truth in the FACT that most EX stones will look larger than most identical weight Fair stones. Put those GIA Fair stones against AGS 0 cut stones and the Truth will be even more evident. I would bet that it would be extremely few, if any GIA Fair stones, that would have the edge to edge sparkle to actually look bigger than an AGS 0 cut diamond of the same weight. Obviously a round brilliant so shallow that it should be called a pancake cut might look bigger, but it would certainly not have the sparkle to make it look nicer.


Wink

yeah,i had one those 60/60 pancake cut with no crown height.

Some 60/60 diamonds are gorgeous and IDEAL by AGS and GIA standards. I have seen one personally.

 

[Isabelle]

Date: 6/29/2010 9:24:11 PM
Author: Rockdiamond
Not to say there are not ''fair'' cut grade stones out there- surely there are plenty of stones GIA would grade ''Fair'' cut grade, if such stones were submitted.

Part of my point is that such stones are virtually never submitted to GIA- therefore ''Fair'' cut graded diamonds are pretty much impossible to find.

There are plenty of VG cut grade stones on the market- many of which will have a larger face up than other stones graded EX cut grade by GIA.


If we did compare a well cut 60/60 to a more traditional Tolkowski 56 table 61 depth stone, many times the 60/60 appears larger- even if the measurements are the same.

Once we can upload photos again, I have some photos to show what I''m talking about.

You can use my friend''s pics of her diamond that I posted a few weeks ago. It looks a lot bigger than 2.10 carat.

 

[Andelain]

My $.02 worth........


I think that a lot of people that think a stone looks larger than it is have been exposed only to "mall cut" diamonds, many of which are very deep. For example I''m wearing a .84 WF ACA that I''ve posted pics of all over SMTB. I had the stone put into a setting that I already had, replacing an old diamond I bought at a strip mall jewelry store many years ago. I had to buy a stone of the same diameter to fit the setting. The old stone weight .97, the new ACA is .84. So my eyes saw that 6.05 mm stone but knew it was a shy carat. That could cause me to look at any .85 to .90 well cut stone and think it was a carat.

 

[Rockdiamond]

If we''re just going by depth, it stands to reason that a 1.00ct diamond of 60% has a greater diameter than one of 61% depth ( to say nothing of 62%- also included in "Ideal Cut" standards)

Although it is true in many cases with round diamonds, it can be shown that there is not always a direct correlation between depth and spread.
There is also the fact that two stones of the same size can look different sizes- based on the way they use the light. Well cut round* diamonds can look larger than other diamonds of the same carat weight that are not as well cut.
I''m not disagreeing with any of this.

Where I disagree is with what is termed "best cut" or "Ideal" in many discussions here. Part of this is because I do prefer a slightly larger table size ( 60%) which is outside many of the "cheat sheets" used on PS. One of the reasons I prefer the more open top of a 60% table is precisely what we''re talking about here- the well cut stone with the 60% will look larger in many cases than one of 55% ( inside the "cheat sheet").

Back in the days before a lot of GIA reports were done - especially on plentiful commercial goods- you would use the diameter as one of the gauges of cut quality.
1.00ct should, in the best circumstance, measure 6.6mm in a really well cut stones.
At the time, many of the really commercial stones -especially from India- were 1.00ct stones that spread 6.1mm- or even less- down to 5.9mm.

I''m sure such stones are still around- but I''m not really exposed to them anymore.

*There are many cases of poorly cut fancy shaped diamonds that are far larger ( surface area) as compared to better cut stones of the same shape and carat weight

 

[yssie]

Date: 6/29/2010 10:34:47 PM
Author: Rockdiamond
If we're just going by depth, it stands to reason that a 1.00ct diamond of 60% has a greater diameter than one of 61% depth ( to say nothing of 62%- also included in 'Ideal Cut' standards)

Although it is true in many cases with round diamonds, it can be shown that there is not always a direct correlation between depth and spread.
There is also the fact that two stones of the same size can look different sizes- based on the way they use the light. Well cut round* diamonds can look larger than other diamonds of the same carat weight that are not as well cut.
I'm not disagreeing with any of this.

Where I disagree is with what is termed 'best cut' or 'Ideal' in many discussions here. Part of this is because I do prefer a slightly larger table size ( 60%) which is outside many of the 'cheat sheets' used on PS. One of the reasons I prefer the more open top of a 60% table is precisely what we're talking about here- the well cut stone with the 60% will look larger in many cases than one of 55% ( inside the 'cheat sheet').

Back in the days before a lot of GIA reports were done - especially on plentiful commercial goods- you would use the diameter as one of the gauges of cut quality.
1.00ct should, in the best circumstance, measure 6.6mm in a really well cut stones.
At the time, many of the really commercial stones -especially from India- were 1.00ct stones that spread 6.1mm- or even less- down to 5.9mm.

I'm sure such stones are still around- but I'm not really exposed to them anymore.

*There are many cases of poorly cut fancy shaped diamonds that are far larger ( surface area) as compared to better cut stones of the same shape and carat weight

Completely agree re. cheat sheets that are too narrow in scope, that are too often misused as strict guidelines

 

[Dancing Fire]

Date: 6/29/2010 10:45:47 PM
Author: yssie


Completely agree re. cheat sheets that are too narrow in scope, that are too often misused as strict guidelines

i use my own "cheat sheet"....54-55% table with a crown height of over 15% and up to 62.2% depth.

 

[Paul-Antwerp]

Garry''s video is extremely interesting in this discussion. It shows how a stone with a bigger diameter can indeed look a lot smaller than the smaller-diameter-stone. So, diameter does not tell you everything, the apparent size of the stone is also related to the cut-quality and the resulting light-return.

Inspired by Garry''s example, I tend to test this out when visiting stores that also carry diamonds of average cut-quality. I take one of our 1.25 Ct-stones for example, and ask them randomly picked 1.50-stones to compare with. This test generally shows that our cut-quality will at least appear the same size as a stone with 10% more weight, often overcoming up to a 20% difference in weight. In other words, our 1.25 will often appear bigger than the random 1.50.

Unfortunately, this does not answer the OP''s question. The GIA-EX-range is rather broad and contains stones of various cut-quality. Most probably a stone with a Fair grade will be cut for weight-retention and will look a lot smaller, but with 90% of the GIA-graded stones at least having a VG-grade, what does that mean?

In summary, cut-quality definitely increases the perceived size of the stones, but a GIA-grade only is insufficient information to confirm this on one specific stone.

Live long,

 

[Rockdiamond]

I kept clicking the wrong link- so I just saw the video.
I''m glad to know we can post youtubes here- I thought they were not allowed.


But the video itself was not very informative as we never got to actually see the two cz''s in normal light.

I do have photos showing two diamonds of nearly identical diameter- and the one which has the larger table looks bigger. The one with the smaller table would certainly be deemed "better cut" if we used PS methodology.

As I mentioned earlier, a "spready" ( shallow) stone rebuffs the theory that a well cut stone will always look larger.
Some well cut stones do look larger, but not all.

 

[John P]

It may help to show Table Flash versus Edge-to-Edge performance.

1. In lighting conditions where table flash is promoted a diamond with a larger table can appear larger than one of equal diameter. The main difference is at the diamond's center.

2. In lighting conditions where edge-to-edge performance is promoted a diamond with better angles/less light leakage can appear larger than one of equal diameter. The main difference is at the diamond's edges (and possibly under-table).

 

[Rockdiamond]

How are you uploading photos John?

I have some shots that I feel are very informative to this subject, but the system won''t allow me any uploading right now

 

[John P]

Date: 6/30/2010 6:31:11 PM
Author: Rockdiamond
How are you uploading photos John?

I have some shots that I feel are very informative to this subject, but the system won''t allow me any uploading right now

I use my supersecret Pricescope "I-agree-leakage-is-real" passcode.

You NY Diamond District guys ain''t in the club.

 

[yssie]

OMG.

Snort.

 

[Garry H (Cut Nut)]

Date: 6/30/2010 3:44:31 PM
Author: Rockdiamond
I kept clicking the wrong link- so I just saw the video.

I'm glad to know we can post youtubes here- I thought they were not allowed.



But the video itself was not very informative as we never got to actually see the two cz's in normal light.


I do have photos showing two diamonds of nearly identical diameter- and the one which has the larger table looks bigger. The one with the smaller table would certainly be deemed 'better cut' if we used PS methodology.


As I mentioned earlier, a 'spready' ( shallow) stone rebuffs the theory that a well cut stone will always look larger.

Some well cut stones do look larger, but not all.

David the first link I posted "shows" the effect, but John has gone even further (as the first class instructor he is).

My contribution with this photo shows that diamond actually has more glare or reflected light than any other gem - the comparison here is with quartz (diamond 18% reflected light and amethyst and citrine 5%), and it is another small part of the reason I tend to give a weighting to shallower stones (and an objection I lodged with GIA's WLR study in 199.

 

[kenny]

Date: 6/30/2010 7:02:57 PM
Author: John Pollard

Date: 6/30/2010 6:31:11 PM
Author: Rockdiamond
How are you uploading photos John?
I have some shots that I feel are very informative to this subject, but the system won''t allow me any uploading right now

I use my supersecret Pricescope ''I-agree-leakage-is-real'' passcode.
You NY Diamond District guys ain''t in the club.

ROFLMFAO!!!

 

[Rockdiamond]

OK John- I give up- leakage sucks.....YOU WIN! ( now can I post my photo?)


heheh

Garry- sorry if I was overly critical, I don''t think the point of that video was to show size specifically.
I really do like your videos- you look great- and speak beautifully.

I was also interested in the graphic you just posted.
How would the color of the diamond affect that 18% light return.
Surely a J returns less than a D- to say nothing of a Fancy Deep Yellow

 

[John P]

Date: 6/30/2010 9:40:28 PM
Author: Rockdiamond

OK John- I give up- leakage sucks.....YOU WIN! ( now can I post my photo?)

I have so totally bookmarked this.


Just tried again and images attach for me. Not sure...usual <100k filesize and unique name, right?
If so ''message admin.''