Confused About Princess Cut Chart

[diamondlove4]

I am trying to use the princess cut reference chart to get an idea of the diamond quality but it seems that every category overlaps a lot that it seems impossible to tell where a diamond falls. I am looking at this chart: http://diamonds.pricescope.com/fnc1.asp

For example, if the diamond I''m trying to look up has a table of 67%, crown of 12.9%, total depth of 71.4%, polish and symmetry is Ex, Girdle is Med to Slightly thick... how do I figure out which of the cut classes this diamond is in? It looks like it could be Class 1A or Class 1B or even 2A since there''s so much overlap. Could someone help with some guidance? Thanks!

 

[stone-cold11]

The stones will have the grade of the worst scoring variable. That stone you list is a 1A but you can't judge a princess cut solely on the numbers, best to have an ASET image.

 

[Lorelei]

Date: 11/8/2009 9:46:24 PM
Author:diamondlove4
I am trying to use the princess cut reference chart to get an idea of the diamond quality but it seems that every category overlaps a lot that it seems impossible to tell where a diamond falls. I am looking at this chart: http://diamonds.pricescope.com/fnc1.asp

For example, if the diamond I'm trying to look up has a table of 67%, crown of 12.9%, total depth of 71.4%, polish and symmetry is Ex, Girdle is Med to Slightly thick... how do I figure out which of the cut classes this diamond is in? It looks like it could be Class 1A or Class 1B or even 2A since there's so much overlap. Could someone help with some guidance? Thanks!

There are various proportion configurations which can result in a beautiful Princess, the above measurements could be one of those. The cut classes are meant to act as a screening tool but with proportion sets like these it would be worth asking for more details such as photos and an ASET image.

 

[FB.]

I would be wary of stones that have proportion sets that spread across several grades - they may contain a bad mis-match of crown and pavilion proportions.
The better stones are likely to have their proportion sets concentrated mostly within one grade (e.g. 1B), with just one or two of their proportions falling one grade either side (e.g 1A & 2A).

 

[diamondlove4]

I unfortunately don''t have access to ASET images as the stone I''m talking about is from Tiffany''s. Apparently, Tiffany''s doesn''t even provide reports like GIA does that shows where inclusions are located, which is disappointing. Even if the stone is of high clarity, it would be nice to see this data.

I''ve read that a stone from Tiffany''s doesn''t immediately equal quality, so I''m trying to take the specs from the actual stone and see how it fares. I know that numbers aren''t everything, but in this case, it''s all I have.

Question... in the diamond chart, the girdle is listed as Very Thin to Slightly Thick in cut classes 1A - 2A, which is a pretty big range. What girdle thickness is really best... is it better to have a thin, medium or slightly thick girdle for a princess cut stone (generally speaking)?

Thanks for the help.

 

[oldminer]

http://gemappraisers.com/oldcutgrade.asp

Go to the above link and select your shape. Then fill in the specs and you will get a final grade per the rules of use. Virtually no one takes the time to understand that there are rules which allow for what passes as apparent overlap and that grading one component at a time is not a worthy task. This all has been automated for many years. It may not be perfect, but no one is offering better so far. It may give you some guidance to compare stones, but it is not a miraculous tool. It was based on observing many diamonds and trying to discern what alterations made a difference one can see. Since different atrtributes alter the overall stone, one can't make a linear system based on single attributes, one at a time.

 

[stone-cold11]

Date: 11/9/2009 1:33:56 PM
Author: diamondlove4
Question... in the diamond chart, the girdle is listed as Very Thin to Slightly Thick in cut classes 1A - 2A, which is a pretty big range. What girdle thickness is really best... is it better to have a thin, medium or slightly thick girdle for a princess cut stone (generally speaking)?

Thanks for the help.

Depends on where the very thin part of the girdle is located. If that is at the corners, no, might be easier to chip during setting and everyday wear. I would prefer a med- slight thick girdle in a princess.

 

[diamondlove4]

Date: 11/9/2009 2:03:21 PM
Author: oldminer
http://gemappraisers.com/oldcutgrade.asp


Go to the above link and select your shape. Then fill in the specs and you will get a final grade per the rules of use. Virtually no one takes the time to understand that there are rules which allow for what passes as apparent overlap and that grading one component at a time is not a worthy task. This all has been automated for many years. It may not be perfect, but no one is offering better so far. It may give you some guidance to compare stones, but it is not a miraculous tool. It was based on observing many diamonds and trying to discern what alterations made a difference one can see. Since different atrtributes alter the overall stone, one can''t make a linear system based on single attributes, one at a time.

This link is perfect, thank you!