princess cut grade

[dshaej]

Hi,

I am looking to purchase a square princess cut, GIA certified diamond, but am having difficulty in determining cut grade. Apparently GIA does not offer a cut grade for princess cuts, and only offers the polish/symmetry grades, which I read were, alone, insufficient in determining the quality of the cut.

I was in the Tiffany store yesterday and saw that their diamonds sparkled and had more fire than the other diamonds I was looking at in this one less commercialized store, and I am thinking that their lighting may have something to do with that. I also know that the quality cut affects a diamond''s brilliance.

So now, I am in the dilemma of not being able to visually compare diamonds (because lighting may be deceptive), but at the same time, I discern the quality of a cut from the GIA reports either because they only have cut grade for round diamonds.

Also, I saw the AGA percentages chart, but those standards aren''t recognised by GIA so I''m not sure I should follow those so strictly.

Any advice/help would be greatly appreciated!

 

[Lorelei]

Welcome to Pricescope,

AGS now provide cut grades for Princess, so you could look for some ASG0 Princess which can be excellently cut and performing diamonds, you are right that GIA does not cut grade fancy shapes at this time.

If you are shopping in jewellery stores, then see if you can find one which stocks AGS0 cut grade Princess, as that will take a lot of the guesswork out of finding a well cut stone. If you are looking online, then stick with vendors who offer these diamonds as in house inventory stones, and you could consider GIA graded Princess if the the diamond has been evaluated for cut quality by an expert vendor. If this is the case, they should have images and detailed photos of the diamond which can help you choose. Cut quality IS so important for the beauty of a diamond, so it is crucial to find a well cut stone. As to any suggested proportion charts, use them as a guide only, as fancy shapes can't be properly judged by numbers, that is why photos and other images are so useful, but above all compare as many diamonds as you can to get a feel for what you find beautiful.

 

[dshaej]

thanks for your reply! i was wondering how respected is AGS? i was particularly interested in a GIA certified diamond because from what i understand, it is the most respected.

 

[Lorelei]

Date: 9/27/2008 12:50:07 PM
Author: dshaej
thanks for your reply! i was wondering how respected is AGS? i was particularly interested in a GIA certified diamond because from what i understand, it is the most respected.

You are most welcome! AGS is highly respected, along with GIA these two labs are considered to be the industry standard and an AGS0 cut grade is very desirable! This info should help, it explains how the grading labs rank.

http://diamonds.pricescope.com/grading.asp

 

[dshaej]

thank you! i was more inclined to purchase a diamond with a gia cert, but now, i think i should look for an ags0 cut grade. it seems to take the question out of what is a good cut for a beginner like me

 

[Lorelei]

Date: 9/27/2008 1:15:44 PM
Author: dshaej
thank you! i was more inclined to purchase a diamond with a gia cert, but now, i think i should look for an ags0 cut grade. it seems to take the question out of what is a good cut for a beginner like me

Indeed finding an AGS0 cut grade Princess does take away a lot of the guesswork and can make life much easier! If you are considering buying online, some of the trusted PS vendors stock them, and we could help you look, or you could contact stores in your area to see who sells ASG0 Princess.

 

[bored1]

It''s important to remember that the cut grade is based on subjective opinions of polled people to begin with. The cut grade for round brilliants came about when diamonds with various proportions, sym, and polish were reviewed by a number of people. They were asked to asses how beautiful they thought the diamond looked. (fire, brilliance (and brilliance patterns), scintillation being a major focus) So it''s best to compare many diamonds and decide which you prefer as opposed to relying too heavily on cut grades. (though personally I wouldn''t touch a diamond that has below vg sym and polish) Light return is largely based on proportions and polish, there is no denying that, still in the end the way a diamond looks is far more important then how it is tagged. Don''t get me wrong, cut grades can be quite helpful, but it is still very new, and very subjective, more so with fancy cuts. Also you are quite right in thinking that the light in which diamonds are displayed will play with the fire, I believe most Tiffany''s stores use halogen lighting which increases fire, it''s a common practice. (and not limited to Tiffany''s or diamonds, even swarovski crystal is typically displayed like this)

 

[dshaej]

I agree that the way it looks is most important, but my reason to resorting to the cut grade is because, as I said, how a diamond looks can be distorted by lights in different store. If I went by the way a diamond looked, I would have most definitely purchased the Tiffany one because it seemed to have a lot of fire under the lighting over another diamond that may have been of higher quality, but not enhanced by lighting.

 

[Lorelei]

Date: 9/27/2008 1:45:06 PM
Author: bored1
It's important to remember that the cut grade is based on subjective opinions of polled people to begin with. The cut grade for round brilliants came about when diamonds with various proportions, sym, and polish were reviewed by a number of people. They were asked to asses how beautiful they thought the diamond looked. (fire, brilliance (and brilliance patterns), scintillation being a major focus) So it's best to compare many diamonds and decide which you prefer as opposed to relying too heavily on cut grades. (though personally I wouldn't touch a diamond that has below vg sym and polish) Light return is largely based on proportions and polish, there is no denying that, still in the end the way a diamond looks is far more important then how it is tagged. Don't get me wrong, cut grades can be quite helpful, but it is still very new, and very subjective, more so with fancy cuts. Also you are quite right in thinking that the light in which diamonds are displayed will play with the fire, I believe most Tiffany's stores use halogen lighting which increases fire, it's a common practice. (and not limited to Tiffany's or diamonds, even swarovski crystal is typically displayed like this)

Welcome to Pricescope bored1,

AGS cut grades do actually make it much easier for inexperienced consumers to buy a well cut Princess - these shapes can be very difficult to evaluate by the numbers and it can be challenging to find well cut stones to compare with in the first place. Also it is more common to find good and above for symmetry and polish in fancy shapes and providing the buyer likes the diamond, no reason to dismiss the stone on that basis, unless it is essential for the buyer to have a higher grade. As it isn't easy to find well cut Princess to begin with, it can make choosing much easier to begin the selection process with diamonds of known cut quality, then pick the diamond with the performance and personality you like from there.

 

[WinkHPD]

Date: 9/27/2008 1:45:06 PM
Author: bored1
It''s important to remember that the cut grade is based on subjective opinions of polled people to begin with. The cut grade for round brilliants came about when diamonds with various proportions, sym, and polish were reviewed by a number of people. They were asked to asses how beautiful they thought the diamond looked. (fire, brilliance (and brilliance patterns), scintillation being a major focus) So it''s best to compare many diamonds and decide which you prefer as opposed to relying too heavily on cut grades. (though personally I wouldn''t touch a diamond that has below vg sym and polish) Light return is largely based on proportions and polish, there is no denying that, still in the end the way a diamond looks is far more important then how it is tagged. Don''t get me wrong, cut grades can be quite helpful, but it is still very new, and very subjective, more so with fancy cuts. Also you are quite right in thinking that the light in which diamonds are displayed will play with the fire, I believe most Tiffany''s stores use halogen lighting which increases fire, it''s a common practice. (and not limited to Tiffany''s or diamonds, even swarovski crystal is typically displayed like this)

What you are saying may be true for GIA, but definitely is NOT TRUE for AGS.

The AGS laboratories did extensive research for some years costing millions of dollars to devise their grading system for rounds and built on that research for the other cuts that they have published grades for. It is determined by many factors, light return, scintillation, dispersion being some of them. None of the factors involed polling observers and getting opinions. Some very accomplished light scientists, including Dr Jose Sassian were involved with this research.

Their work was so extensive that the scientists working on this research presented the first major peer reviewed work on the light science involved in grading diamonds to be published in a light sciences journal. This peer reviewed paper was so well done that it in fact was the cover story for that month''s Journal. John Pollard posted the exact name of the article and the Joural and rather than post what I think I rememer I will hope that he takes the time out of his trip to Belgium to insert it and the link to it.

As a side note. The AGS Laboratory was formed when GIA refused to come up with a cut grade for the AGS membership who were tired of seeing poorly cut diamonds offered to the public as equal in value to the well cut diamonds that were becoming available. It was only after the AGS had done their cut research that the GIA was forced to focus on this also by market demand. The GIA did rely heavily on the opinions of observers, both trained and untrained as you stated.

Wink

 

[WinkHPD]

Lorelei,

As always you have given great council, obviating the necessity for me to add much, so I did not.

Wink

 

[Lorelei]

Date: 9/27/2008 2:24:14 PM
Author: Wink
Lorelei,

As always you have given great council, obviating the necessity for me to add much, so I did not.

Wink

Thank YOU Wink for your excellent post! ( as usual!)

I wonder if this is the link of John's you referred to?

https://www.pricescope.com/community/threads/scientific-recognition-for-ags-cut-grade-technology.71945/

 

[dshaej]

so i''ve been just browsing around, trying to learn more about diamonds.

what are your opinions about these two, and if you had to pick one, which one would you go with?

http://www.whiteflash.com/princess/Princess-cut-diamond-1204595.htm#
http://www.whiteflash.com/aca_princess/A-Cut-Above-Princess-cut-diamond-336523.htm#

 

[WinkHPD]

Date: 9/27/2008 2:33:15 PM
Author: Lorelei

Date: 9/27/2008 2:24:14 PM
Author: Wink
Lorelei,

As always you have given great council, obviating the necessity for me to add much, so I did not.

Wink

Thank YOU Wink for your excellent post! ( as usual!)

I wonder if this is the link of John''s you referred to?

https://www.pricescope.com/community/threads/scientific-recognition-for-ags-cut-grade-technology.71945/

It would indeed!.

Recommended reading for all of you light scientists.

Wink

 

[WinkHPD]

Date: 9/27/2008 4:09:52 PM
Author: dshaej
so i''ve been just browsing around, trying to learn more about diamonds.

what are your opinions about these two, and if you had to pick one, which one would you go with?

http://www.whiteflash.com/princess/Princess-cut-diamond-1204595.htm#
http://www.whiteflash.com/aca_princess/A-Cut-Above-Princess-cut-diamond-336523.htm#

If you are asking me I must respectfully decline. Forum rules rightfully prohibit vendors from commenting on other vendor''s stones with the exception of correcting any mistatements of fact. I will say that WhiteFlash is one of several highly respected vendors on this site.

Wink

 

[dshaej]

i was just asking anyone in general who might have a comment to make

if such forum rule exists, non-vendors, please reply if you have any advice!

 

[stone-cold11]

Date: 9/27/2008 4:09:52 PM
Author: dshaej
so i''ve been just browsing around, trying to learn more about diamonds.


what are your opinions about these two, and if you had to pick one, which one would you go with?


http://www.whiteflash.com/princess/Princess-cut-diamond-1204595.htm#

http://www.whiteflash.com/aca_princess/A-Cut-Above-Princess-cut-diamond-336523.htm#

My preference will be the ACA cut. From the pics, it looks pretty eye-clean to me, F is still in the colorless range, the IS and ASET pics also looks better than the ES stone.

 

[jstarfireb]

It''s a toss-up; the differences look pretty subtle to me. The ASETs are pretty similar, though the ACA slightly edges out the ES; you won''t notice a difference between D and F color or between VS1 and an eye-clean SI1; proportions are more square in the ACA but really not that far off in the ES. Both are AGS0 and bound to be beauties! The one thing that would pull me toward the D/VS1 would be the strong blue fluor, which I absolutely love! Fluorescence is totally about personal preference though. Some seek it out, and some specifically avoid it. I believe ACA stones by definition can''t have any more than faint fluorescence. If you like the D/VS1, just make sure the very thin part of the girdle won''t be a durability issue.

 

[Lorelei]

Date: 9/27/2008 4:09:52 PM
Author: dshaej
so i''ve been just browsing around, trying to learn more about diamonds.

what are your opinions about these two, and if you had to pick one, which one would you go with?

http://www.whiteflash.com/princess/Princess-cut-diamond-1204595.htm#
http://www.whiteflash.com/aca_princess/A-Cut-Above-Princess-cut-diamond-336523.htm#

You can''t go wrong with either, both beautifully cut, if the SI clarity is eyeclean to your standards then pick the one which appeals to you most.