What to look for when viewing a stone with less than excellent polish?

[NJDeac]

I have a local jeweler who has called in a stone for me to look at with the following specs:

GIA Report
Size: 1.53 ct
Color: I
Clarity: VS1
Cut: Ex
Polish: VG
Symm: Ex
Table: 55%
Depth: 62.5%
Crown: 34.5 deg
Pav: 40.6 deg
Grdl: Med-STK

He also assures me it is a H&A, which I will be verifying at the time I look at the stone (they have a H&A viewer in the store). I also just received my idealscope and ASET tool so I can hopefully see with my own eyes whether the stone is a strong performer.

The reason I''m posting, is because nearly every stone I''ve looked at thus far has been Ex/Ex/Ex, and this will be the first that has a VG polish. From looking at the various resources here on PS and elsewhere, the conclusion seems to be that a rating in this category is very unlikely to affect the light performance of the stone, or even be easily discernible. Is this accurate? Are there particular negatives associated with a less than excellent polish that I should be aware of and look for when examining the stone?

The stone is being offered at a very attractive price (comparable to and even better than some online retailers but at a B&M store), so I''m wary for anything that might make the stone a dud that might not be immediately apparent. However, other than the slightly high depth percentage (without a steep crown or pavilion angle), the numbers seem good.

 

[stone-cold11]

yap, numbers look good. No way to tell the polish difference between VG and /Ex as far as I know, maybe someone else can.

 

[Rockdiamond]

Virtually impossible to see the difference between Good, and EX Polish without a microscope in the vast majority of cases- and sometimes incredibly difficult even WITH a microscope!

Don''t let that single aspect color your judgement.

 

[Lorelei]

Date: 3/31/2010 2:55:36 PM
Author:NJDeac
I have a local jeweler who has called in a stone for me to look at with the following specs:

GIA Report
Size: 1.53 ct
Color: I
Clarity: VS1
Cut: Ex
Polish: VG
Symm: Ex
Table: 55%
Depth: 62.5%
Crown: 34.5 deg
Pav: 40.6 deg
Grdl: Med-STK

He also assures me it is a H&A, which I will be verifying at the time I look at the stone (they have a H&A viewer in the store). I also just received my idealscope and ASET tool so I can hopefully see with my own eyes whether the stone is a strong performer.

The reason I'm posting, is because nearly every stone I've looked at thus far has been Ex/Ex/Ex, and this will be the first that has a VG polish. From looking at the various resources here on PS and elsewhere, the conclusion seems to be that a rating in this category is very unlikely to affect the light performance of the stone, or even be easily discernible. Is this accurate? Are there particular negatives associated with a less than excellent polish that I should be aware of and look for when examining the stone?

The stone is being offered at a very attractive price (comparable to and even better than some online retailers but at a B&M store), so I'm wary for anything that might make the stone a dud that might not be immediately apparent. However, other than the slightly high depth percentage (without a steep crown or pavilion angle), the numbers seem good.

The basic numbers do look good, see what you think of the h&a patterning when you see it, in case you haven't seen it below is the h&a tutorial from the Pricescope knowledge section,

https://www.pricescope.com/wiki/diamonds/hearts-and-arrows-diamonds/

As Stone says, good and above for polish and symmetry is usually indistinguishable to the naked untrained eye, some purchasers of top cut h&a diamonds prefer excellent or ideal for each, depending on the grading lab, but it depends on you if you like the diamond and it shows a crisp and precise h&a pattern or close to it.