Who knows about princess cut diamonds?

[cguirguis]

Hey everyone,

I''ve read a few of the threads here over the past couple of days and felt that I could get some much needed feedback by asking for some advice. I''ve been doing a lot of research and recently found a stone on Union Diamond that I feel is a great deal. My girlfriend absolutely wants a princess cut and she has thin fingers, so a weight of 1.0 carat is sufficient, although I''m trying to go a bit higher. Here are the specs for the diamond I''ve found... look over them and let me know what you think!

Weight: 1.11 ct
Cut: Very good
Color: D
Clarity: VS1
Symetry: Ex
Polish: Ex
Depth: 68.7%
Table: 71.0%
L/W: 1.03
Girdle: Thick - Very thick
Fluorescence: Medium blue (asked about this and was told there is no haze)
Price: $5669 (wire transfer)

I emailed UD about this diamond and so far have received excellent support from one of their gemologists. When I asked about the clarity, this is what she told me:
To answer your question, while I have not seen this particular Diamond, I have talked with my associate who is holding the stone. This is a VS1 graded stone. That is Very clean, and what minor inclusions do lay within the Diamond, should not affect the appearance, brilliance, or durability of the Diamond what so ever. I hope this has helped. There is a small cloud under the surface to the side of the table and a very tiny feather near a star facet. Both a very minor, almost insignificant.

What do you guys feel about this? I appreciate any feedback.

Thanks,

Chris

 

[Lorelei]

Welcome to Pricescope!

Unfortunately, we can't give any meaningful input without detailed photographs of the diamond and preferably images such as ASET if available. Fancy shapes such as Princess cannot be properly evaluated by the numbers, so ask UD if they can email some pics of the diamond to you, then we can go from there. I would also personally prefer to see the girdle be a little less, such as slightly thin to slightly thick, but the polish and symmetry grades are good. Do you have the diameter measurements of the diamond? Does it have a GIA report or other lab?

 

[John P]

Cut: Very good

Who assigned the cut grade?

Girdle: Thick - Very thick

Not a good sign. It may be hiding excess weight in the girdle. What are the dimensions in mm?

 

[cguirguis]

Thanks John and Lorelei. I felt a bit uncomfortable with the girdle width as well, but everything else seemed to check out, and I''ve seen Ideal cut diamonds with the same girdle thickness so I figured it wasn''t a huge deal.

UD doesn''t have pictures of the diamond as they do not carry it in-house (I''ve seen a few other vendors listing the same diamond). The cut was assigned by GIA, which from what I''ve read is the most respected.

The link below will tell you the dimensions for the diamond:
http://www.uniondiamond.com/diamonds/diamonds.php?mod=search&search_type_id=2&action_type_id=2&item_id=AA966709

Appreciate any more feedback you can provide.

Thanks,

Chris

 

[John P]

Hi Chris,

I think you have come across some misinformation...

Date: 7/23/2008 2:25:21 PM
Author: cguirguis

Thanks John and Lorelei. I felt a bit uncomfortable with the girdle width as well, but everything else seemed to check out, and I've seen Ideal cut diamonds with the same girdle thickness so I figured it wasn't a huge deal.

The only lab grading princess cuts is AGS. Their "ideal" grade does not permit a girdle thickness average above slightly thick. Whoever you have seen assigning "ideal" cut grades to diamonds with tk-vtk girdles does not have very strong standards.

The cut was assigned by GIA, which from what I've read is the most respected.

Impossible. GIA doesn't grade cut for princess shapes.

I suggest you get an ASET image of the diamond. Perhaps more importantly, find out who labeled the diamond 'very good' in cut, and check on who is allowing diamonds with such thick girdles to be labeled 'ideal.' It is definitely not in-line with the top tier labs.

 

[jstarfireb]

Princesses face up smaller than rounds, so I would definitely be wary of that girdle! You don''t want your stone to look any smaller than it has to. You''re basically paying for weight that you''re not seeing with this stone.

I would also go WAY lower than D in color. I have an ideal cut I color princess that looks like an F when viewed from the top. Most people will not be able to tell the difference between D and G-H in color, so my feeling is "why pay for what you can''t see?" You could do the same with the color; VS1-VS2 are great, but you can get an eye-clean SI1 or SI2 and pay much less. You might be interested in this article on color. Good luck!

 

[cguirguis]

Hi John,

Are you sure? Because GIA is clearly the lab that graded this diamond... as you can see from the report I''ve uploaded here:
http://chrisguirguis.com/GIA_report.jpg

Princess cut the same as modified square brilliant right? I''ve seen quite a few princess/square diamonds graded by GIA, even in retail stores.

And could you tell me what an ASET image is? How useful is it?

Thanks,

Chris

 

[jstarfireb]

Yes, that appears to be a GIA-graded stone, but I think John's point was that AGS is the only lab that grades princesses for cut quality. Lots of labs will grade princess cut stones; only AGS will say "very good" or "good" or "ideal" for cut quality. Your GIA document doesn't have any grade like that, so I'm not sure where you heard it was graded "very good" for cut.

ETA: I'm not sure what your budget is, but here's an ideal cut D princess. As I mentioned, I'd go down in color to something like this: 1.25 I VS2...look at the price difference! Both are ideal cut stones and should look beautiful. But you can get a bigger stone for less if you drop color and clarity. 1.25 is a really nice size for a princess! The medium blue fluorescence will also make that I diamond look whiter.

 

[John P]

Date: 7/23/2008 5:43:50 PM
Author: cguirguis
Hi John,

Are you sure? Because GIA is clearly the lab that graded this diamond... as you can see from the report I''ve uploaded here:
http://chrisguirguis.com/GIA_report.jpg

Princess cut the same as modified square brilliant right? I''ve seen quite a few princess/square diamonds graded by GIA, even in retail stores.

And could you tell me what an ASET image is? How useful is it?

Thanks,

Chris

Chris,

Positive sir.

GIA grades all shapes but you cited a cut grade of "Very Good" in the original post... GIA does not evaluate cut quality in shapes other than round brilliant. It''s unfortunate since cut is what gives the diamond its life, sparkle, kick, etc. I suggest someone has slapped a label of "very good" on the diamond. You should probably see what that means. It may be equivalent to a car dealer saying a certain car is a "cream puff." Ok. Thanks car guy, but what does that imply?

An ASET image shows angular spectrum for a diamond. The approach has been used since the 1970s-80s to assess and design diamond cut quality, and is the basis for the AGS labs light performance grade for diamonds.

Here is a thread with some info: https://www.pricescope.com/community/threads/why-we-prefer-aset-to-ideal-scope-with-fancy-shapes.73949/

 

[John P]

Date: 7/23/2008 5:50:48 PM
Author: jstarfireb
Yes, that appears to be a GIA-graded stone, but I think John''s point was that AGS is the only lab that grades princesses for cut quality. Lots of labs will grade princess cut stones; only AGS will say ''very good'' or ''good'' or ''ideal'' for cut quality. Your GIA document doesn''t have any grade like that, so I''m not sure where you heard it was graded ''very good'' for cut.

ETA: I''m not sure what your budget is, but here''s an ideal cut D princess. As I mentioned, I''d go down in color to something like this: 1.25 I VS2...look at the price difference! Both are ideal cut stones and should look beautiful. But you can get a bigger stone for less if you drop color and clarity. 1.25 is a really nice size for a princess! The medium blue fluorescence will also make that I diamond look whiter.

Thanks jstarfireb. Just so.

 

[cguirguis]

Hi again,

I decided not to go with the previous diamond I mentioned due to the large girdle thickness. I have found a new diamond which I think is beautiful (and very well priced) from jamesallen.com. Any thoughts on this?

Thanks,

Chris

---------------------------------------------

Item Number: 1101790
Shape: Princess
Carat weight: 1.01
Cut: Ideal
Color: F
Clarity: VS1
Certificate: GIA

Depth: 69.9%
Table: 72.0%
Polish: Excellent
Symmetry: Very Good
Girdle: Very thin to thin
Culet: None
Fluorescence: None
Measurements: 5.85*5.69*3.98
Ratio: 1.03

 

[cguirguis]

I forgot to add that with this diamond I''m concerned with the very thin girdle (especially since it is a princess cut) and worry that it could be chipped during setting/wear. Seems to be the opposite issue than that of the previous stone I mentioned.

Any advice would be appreciated.

Here is a picture of the diamond:
http://www.chrisguirguis.com/volairus/DiamondComparison.JPG


It''s the one on the right. I was interested in both and Jim from jamesallen.com took a picture of the two side by side to compare them. His gemologist''s slight preference was with this one (on the right).

 

[jstarfireb]

Date: 8/1/2008 11:33:02 AM
Author: cguirguis
I forgot to add that with this diamond I''m concerned with the very thin girdle (especially since it is a princess cut) and worry that it could be chipped during setting/wear. Seems to be the opposite issue than that of the previous stone I mentioned.


Any advice would be appreciated.


Here is a picture of the diamond:

http://www.chrisguirguis.com/volairus/DiamondComparison.JPG



It''s the one on the right. I was interested in both and Jim from jamesallen.com took a picture of the two side by side to compare them. His gemologist''s slight preference was with this one (on the right).

As is mine. The one on the left seems to have more leakage.

That looks like a nice stone, although I would probably go for a table smaller than the depth (and a slightly thicker girdle for the reason you mentioned). Make sure you set it in V-prongs and insure that baby if you get it. Are you OK with the dimensions (it''s a bit off-square)? My princess is off by 0.12 and it''s just barely visible to the naked eye; this is off by 0.16. We would have to see an IS and ASET image to really make the call. At this point, I would still go for
the one I mentioned from GOG, given the info that''s available online now, also depending on the difference in price between them.

 

[Lorelei]

It actually looks like a lovely stone in the pic, if Jim at JA has access to this diamond, get him to check out the girdle for you, it may only be a small area and not of concern - the very thin area, or it could go the other way, Jim will be honest with you.

 

[dbsdiamonds]

I love the "experts" on this site. This has been fun to join and watch the angles presented. The diamond info is readily available to the insiders.

No fret, the diamond is awesome. If I''m getting a 1ct pc then I would want 5.5mm or larger to project the full size of 1ct. Ideally in the 5.6 to 5.7mm square range. This 1.11ct you refer to is 5.9x5.7 rounded. So presents as a 1.10ct+ size should. There is no need for all these sales gimmick cut tools or beating up the girdle thickness.

Plus with ex/ex on polish and symmetry, very rare stats from GIA. Fluorescence is medium, I''m a fan of fluorescence and not a buyer into the nonsense of "none" being the best. All you gotta do is read up on www.gia.edu on their studies and of course 23+ years of looking at diamonds helps come to this conclusion as well.

It''ll be a great stone.

Marty
CEO/Pres.
www.dbsdiamonds.com

 

[Lorelei]

Date: 8/1/2008 1:34:22 PM
Author: dbsdiamonds

I love the ''experts'' on this site. This has been fun to join and watch the angles presented. The diamond info is readily available to the insiders.

No fret, the diamond is awesome. If I''m getting a 1ct pc then I would want 5.5mm or larger to project the full size of 1ct. Ideally in the 5.6 to 5.7mm square range. This 1.11ct you refer to is 5.9x5.7 rounded. So presents as a 1.10ct+ size should. There is no need for all these sales gimmick cut tools or beating up the girdle thickness.

Plus with ex/ex on polish and symmetry, very rare stats from GIA. Fluorescence is medium, I''m a fan of fluorescence and not a buyer into the nonsense of ''none'' being the best. All you gotta do is read up on www.gia.edu on their studies and of course 23+ years of looking at diamonds helps come to this conclusion as well.

It''ll be a great stone.

Marty
CEO/Pres.
www.dbsdiamonds.com

ASET may be a gimmick to you, but it has been very useful to people here in evaluating fancy shapes when they are buying online and can''t see the diamond.

 

[dbsdiamonds]

If a specific tool is not industry accepted or used or factually proven as the "end all, be all" evaluator then yes, it is a guide, and can be used as a gimmick.

A number of these tools are skewed to the percentages set forth in the program doing the analysis. I''m sure you''d concur that it''s a case by case basis on each gem.

However, when one really cuts down to the core of this can one really see a 2.7 vs. a 2.5? Can a 55% table be seen by a person vs. a 56%? Can one see 210 twinkles of brilliance vs. 208? Is there a $50, or $500, or $10,000 difference attached that is worthy? Should one trade D color for F color on similarly monster cut princess diamonds or loose weight and measurements for a reading that is definitely not visible?

I''ve had this discussion with RocDoc 9 years ago when I started my company online. God rest his soul.

Whatever it takes for the consumer to find the best diamond for his/her budget.

On another note you are a great responder and helper to the questions from people on this site.

Marty
CEO/Pres
www.dbsdiamonds.com

 

[Lorelei]

Date: 8/1/2008 2:06:47 PM
Author: dbsdiamonds

If a specific tool is not industry accepted or used or factually proven as the ''end all, be all'' evaluator then yes, it is a guide, and can be used as a gimmick.

A number of these tools are skewed to the percentages set forth in the program doing the analysis. I''m sure you''d concur that it''s a case by case basis on each gem.

However, when one really cuts down to the core of this can one really see a 2.7 vs. a 2.5? Can a 55% table be seen by a person vs. a 56%? Can one see 210 twinkles of brilliance vs. 208? Is there a $50, or $500, or $10,000 difference attached that is worthy? Should one trade D color for F color on similarly monster cut princess diamonds or loose weight and measurements for a reading that is definitely not visible?

I''ve had this discussion with RocDoc 9 years ago when I started my company online. God rest his soul.

Whatever it takes for the consumer to find the best diamond for his/her budget.

On another note you are a great responder and helper to the questions from people on this site.

Marty
CEO/Pres
www.dbsdiamonds.com

I see where you are coming from Marty, thank you for your post!

 

[John P]

Date: 8/1/2008 2:06:47 PM
Author: dbsdiamonds

If a specific tool is not industry accepted or used or factually proven as the 'end all, be all' evaluator then yes, it is a guide, and can be used as a gimmick.

Hi Marty,

It may interest you to know that ASET fundamentals are the foundation of the industry's first scientifically vetted cut grading system. Unlike the devices developed for sales, the AGS system is rooted in reflector technology developed in factories by diamond cutters and fine-make researchers engaged in studies of angular spectrum in the 1970s and 80s. Okuda, Al Gilbertson, Garry Holloway and Dr. Jose Sasian are among those who have been involved-in and evolved those studies.

AGS was awarded three patents in-line with their grading system, the foundation of which was peer-reviewed and published in "Optical Engineering," the monthly journal of SPIE (story here). This is the first scientifically vetted, repeatable light performance grading system in use by a major lab. Additionally, it is the first major cut grading system in use for fancy shapes.

Some of the more cut focused sellers with a presence on this site provide ASET images of their diamonds. With some training it is fairly easy to draw logical and repeatable conclusions about the brightness and contrast of a stone based on its angular spectrum.

If you're interested, here is the AGS paper. It's a great read: http://www.agslab.com/spie/spie_lo_res.pdf

 

[cguirguis]

Marty, Lorelei and jstarfireb:

Thanks for your replies. I''m waiting to hear Jim''s feedback regarding the girdle thickness (or thinness, rather), to see if there will be any durability issues.

Marty, I think you were responding to the first stone I suggested though, not the second one. Could you tell me what you think about the second? Thanks.

jstarfireb, why would you go with a smaller table than depth? Is there a general rule that these diamonds are more brilliant/visually appealing than the other way around? Also, I''m ok with the l/w ratio of 1.03. Aside from making the diamond look more rectangular, is there any reason why this should be avoided? Again, in terms of brilliance?

Thanks,

Chris

 

[John P]

Date: 8/1/2008 11:33:02 AM
Author: cguirguis

I forgot to add that with this diamond I''m concerned with the very thin girdle (especially since it is a princess cut) and worry that it could be chipped during setting/wear. Seems to be the opposite issue than that of the previous stone I mentioned.

As Lorelei mentioned, the ''vtn'' descriptor could be one tiny position on the girdle, or it could imply an area of significance. Ask your seller to describe what the ramifications are.

For example, here is a princess with a girdle described as very thin - medium. Almost the entire girdle is medium. The vtn on the grading report referred to an indented natural on a corner (arrow). In this case the stonesetter was careful to protect the corner. No problems (photo by Brian Gavin).

Much more on girdles, if you''re interested, in this thread: https://www.pricescope.com/community/threads/girdles.66614/

 

[John P]

Date: 8/1/2008 11:11:23 AM
Author: cguirguis

Item Number: 1101790
Shape: Princess
Carat weight: 1.01
Cut: Ideal
Color: F
Clarity: VS1
Certificate: GIA

Depth: 69.9%
Table: 72.0%
Polish: Excellent
Symmetry: Very Good
Girdle: Very thin to thin
Culet: None
Fluorescence: None
Measurements: 5.85*5.69*3.98
Ratio: 1.03

F VS1 is a great color/clarity combination. Ask about the girdle (per above). There is no way to predict the performance of a fancy shape based on numbers; there are too many variables. An ASET image would be helpful to us, but your best bet without the AGS Ideal grade in light performance or an ASET to show angular spectrum is to dialogue with those experts who have the diamond in-hand. This is one reason online sellers extend a generous return period; you will have time to verify what they tell you - whether on your own or through an independent appraisal.

Princess cuts can vary quite a bit in general appearance, particularly in table size and pavilion faceting. In common sizes a princess cut with 2 or 3 chevrons will have a different quality to its scintillation than one with 4 or 5 chevrons (depending on quality of light return and cut precision). Similarly, a princess with a small table/high crown can tend towards more fire in its performance qualities than a spready table/low crown, which may tend towards brightness. And of course your ability to see any of these nuances (scintillation quality, fire, brightness, contrast...) is dependant on the diamond's overall cut quality more than anything else.

 

[jstarfireb]

Date: 8/1/2008 2:52:01 PM
Author: cguirguis
jstarfireb, why would you go with a smaller table than depth? Is there a general rule that these diamonds are more brilliant/visually appealing than the other way around? Also, I''m ok with the l/w ratio of 1.03. Aside from making the diamond look more rectangular, is there any reason why this should be avoided? Again, in terms of brilliance?

Honestly? I''ve just been told by people with much more expertise than myself that the table should be smaller than the depth in a princess cut. I really don''t know why, but I trust those who say it.

The L/W ratio is only a visual thing; I think most people find square princesses more appealing than rectangular ones. As such, there is a price premium that comes with a more square stone, and you can save some cash by getting a stone that''s a little off square like yours or mine. You just have to make sure it''s appealing to your eyes (and hers)! As far as I know, there''s no effect on brilliance.

I think the stone looks very pretty, as I mentioned; there are just those little nitpicky things such as the girdle possibly being an issue. And I also think F is a bit of overkill in the color department, but that''s also personal preference. As an example, most people will say VVS2 is clarity overkill, and that''s what my stone is (I didn''t have a particular clarity preference; it''s just that the stone I liked and that fit in budget happened to be higher in clarity than I needed).

I would still request IS and ASET images, which James Allen can provide (they''ve done it before for other PSers). Seeing a close-up picture of the diamond is good, but it''s not quite objective enough for me. You never know what the lighting environment is, what anyone did to touch up the photo, etc. You may not be able to tell from a picture that there''s a bunch of leakage when viewed from a certain angle, or a window effect, etc. IS/ASETs are more helpful to me when you can''t see the diamond in person, because they''ll tell you how well the diamond reflects light.

 

[Lorelei]

Date: 8/1/2008 5:51:25 PM
Author: jstarfireb

Date: 8/1/2008 2:52:01 PM
Author: cguirguis
jstarfireb, why would you go with a smaller table than depth? Is there a general rule that these diamonds are more brilliant/visually appealing than the other way around? Also, I''m ok with the l/w ratio of 1.03. Aside from making the diamond look more rectangular, is there any reason why this should be avoided? Again, in terms of brilliance?

Honestly? I''ve just been told by people with much more expertise than myself that the table should be smaller than the depth in a princess cut. I really don''t know why, but I trust those who say it.

The L/W ratio is only a visual thing; I think most people find square princesses more appealing than rectangular ones. As such, there is a price premium that comes with a more square stone, and you can save some cash by getting a stone that''s a little off square like yours or mine. You just have to make sure it''s appealing to your eyes (and hers)! As far as I know, there''s no effect on brilliance.

I think the stone looks very pretty, as I mentioned; there are just those little nitpicky things such as the girdle possibly being an issue. And I also think F is a bit of overkill in the color department, but that''s also personal preference. As an example, most people will say VVS2 is clarity overkill, and that''s what my stone is (I didn''t have a particular clarity preference; it''s just that the stone I liked and that fit in budget happened to be higher in clarity than I needed).

I would still request IS and ASET images, which James Allen can provide (they''ve done it before for other PSers). Seeing a close-up picture of the diamond is good, but it''s not quite objective enough for me. You never know what the lighting environment is, what anyone did to touch up the photo, etc. You may not be able to tell from a picture that there''s a bunch of leakage when viewed from a certain angle, or a window effect, etc. IS/ASETs are more helpful to me when you can''t see the diamond in person, because they''ll tell you how well the diamond reflects light.

JStar, I haven''t known JA to provide ASET images unfortunately but they will IS.

 

[honey22]

Date: 8/1/2008 1:48:58 PM
Author: Lorelei

Date: 8/1/2008 1:34:22 PM
Author: dbsdiamonds

I love the ''experts'' on this site. This has been fun to join and watch the angles presented. The diamond info is readily available to the insiders.

No fret, the diamond is awesome. If I''m getting a 1ct pc then I would want 5.5mm or larger to project the full size of 1ct. Ideally in the 5.6 to 5.7mm square range. This 1.11ct you refer to is 5.9x5.7 rounded. So presents as a 1.10ct+ size should. There is no need for all these sales gimmick cut tools or beating up the girdle thickness.

Plus with ex/ex on polish and symmetry, very rare stats from GIA. Fluorescence is medium, I''m a fan of fluorescence and not a buyer into the nonsense of ''none'' being the best. All you gotta do is read up on www.gia.edu on their studies and of course 23+ years of looking at diamonds helps come to this conclusion as well.

It''ll be a great stone.

Marty
CEO/Pres.
www.dbsdiamonds.com

ASET may be a gimmick to you, but it has been very useful to people here in evaluating fancy shapes when they are buying online and can''t see the diamond.

Ditto Lorelei! The last time I heard someone tell me that an IS or ASET image was a sales gimmick, they were trying to offload a lovely piece of frozen spit onto me!

I love the ''experts'' on this site.

I really hope I have misread your sarcastic tone here, as there are many lovely people here who post regularly to help others out in finding a great stone. I am one of those people. No we are not ''experts'' but we do like to share our knowledge of diamonds with others who come here asking for opinions and help. We also do this to protect them from vendors who use (for example) the following misleading statements: "There is no need for all these sales gimmick cut tools"

 

[DiamondExpert]

"The L/W ratio is only a visual thing; I think most people find square princesses more appealing than rectangular ones. As such, there is a price premium that comes with a more square stone, and you can save some cash by getting a stone that''s a little off square like yours or mine. You just have to make sure it''s appealing to your eyes (and hers)! As far as I know, there''s no effect on brilliance."

I would expect a near/absolutely square Princess to perform better/slightly better than a rectangular/very rectangular one...strong 4-fold symmetry should be better than 2-fold for overall light performance...but, I agree it would be a matter of degree...just how far out of symmetry a particular stone might be and how different/similar the pav/crown angles on the short/long sides are, how many chevrons are cut, size/position/# of virtual facets, contrast pattern, and so on.