Fancy Cut Stones Polish/Symmetry Question

[acgirl]

Hi Again,
I''ve been looking at Ovals again tonight and was wondering why I find so few have polish and symmetry rated Excellent/Excellent. As a test I looked at several websites and found only a couple of ovals that had that rating. Almost everything else seemed to be Very Good/Very Good. Is it just not as important for fancy cut stones? I looked at Emerald, Pear and Princess and found that there were more for those cuts but still very rare to find EX/EX in them as well.

 

[acgirl]

Anyone have any ideas on this?

 

[strmrdr]

lack of premium for it means very few will spend the time to do it.
If it comes out that way kewl if not thats the way it goes out the door.

 

[oldminer]

Diamonds cut to fancy shapes are made from rough that does not lend itself to cutting in a round shape. It is sometimes a material which is more difficult to cut as the crystal structure may be a bit stretched. Also, since there is no premium for Exc/Exc in fancy shapes, as you have been already told, there is really very little chance of finding such a stone. Besides, it probably will have no visual difference anyway. Exc/Exc is a harsplitting sort of grade, and has nothing of great importance to the beauty of a diamond. However, for those who seek out the very best, for personal reasons, there is merit to this very exact grading for them.

 

[strmrdr]

Well said Dave.

 

[acgirl]

Thanks to both of you for the feedback. David, I seem to recall seeing another post of yours (I think it was you) in which it was said to try to get a stone that is graded at least very good for polish and symmetry. Was it you that posted that and, if not, do you think there is a minimum one should look for in polish/symmetry all other things, (cut, clarity, etc.) being equal? I noticed on the GIA website that it says the quality of the polish affects scintillation. (Though to what degree it doesn''t say.) Having asked that question, I''m sure it''s still more applicable to rounds than fancies, but still wondered your opinion.
I know these kinds of questions can seem rather academic to the Pros around here, but there are actually very few jewelry stores in my area that stock quality stones, especially fancies, so the certs are about all we buyers have to go on.

 

[strmrdr]

For me its a stone by stone decision.
Are a lot of the meet points off or only one?
Are a lot of facets only good polish or just 1?

For buying online vg/vg is safer but with a trusted vendor looking them over first its not a huge problem.

For asschers its rare to see a well cut one below vg/vg but it does happen expecialy in the older ones.

 

[valeria101]

Date: 9/23/2005 10:03:27 AM
Author: acgirl

GIA website that it says the quality of the polish affects scintillation. (Though to what degree it doesn't say.)

If you were hunting old cuts (or damaged diamonds - but that's ... weird), that would be the only way to see faults of polish and facet meets large enough to be visible. Among modern diamonds is rare (you would probably see a 'fair' GIA grade for the issue at stake) and more likely for diamonds of rather low quality from some other point of view as well. Maybe you do get in luck, but chances are the local jewelry shops would not be able to source such an example to show.

Strm seems to have taugher standards - I can't tell these grades above 'Good' 'in person' for the life of me. With one half of an exception: optical symmetry does show, and the 'symmetry' grade on lab reports seems to be correlated with optical symmetry up to a point. I am not sure if this effect has 'hard science' behind or rather it is mere coincidence: better cut diamonds get all the details of cut done better just because they have been lucky to get on the right assembly line

GIA did have something to say about how much its own polish and symmetry grades matter to buyers... but maybe this bit of information did not make it on their website. It did make it towards the end of the article on GIA cut grades published on this forum (see the 'Pricescope Diamond Journa;' on Pricescope's first page).

Link to article page

Given that the same grading cathegories are applied to all diamond shapes, I have no reason to believe that these two finish grades would somehow be more important for one sort of modified brilliant than the next. Perhaps the limited amount of refferences about cut grading for fancies make these sound important against the vacuum... but that's not a good reason, IMO.


Hope the 0.2 worth helps

 

[windowshopper]

Date: 9/23/2005 10:03:27 AM
Author: acgirl
Thanks to both of you for the feedback. David, I seem to recall seeing another post of yours (I think it was you) in which it was said to try to get a stone that is graded at least very good for polish and symmetry. Was it you that posted that and, if not, do you think there is a minimum one should look for in polish/symmetry all other things, (cut, clarity, etc.) being equal? I noticed on the GIA website that it says the quality of the polish affects scintillation. (Though to what degree it doesn't say.) Having asked that question, I'm sure it's still more applicable to rounds than fancies, but still wondered your opinion.
I know these kinds of questions can seem rather academic to the Pros around here, but there are actually very few jewelry stores in my area that stock quality stones, especially fancies, so the certs are about all we buyers have to go on.

i am so NOT an expert but i will say this: if you were buying a round then I do believe that it should have a minimum of VG/VG because i think it matters more for those stones. Per Dave's comments that the crystal structure of fancies does not lend itself to perfect symmetry and ease of cutting in diametrically opposing shapes I think a symmetry of Good for a fancy is actually probably the equivalent of Very Good in a round. I do believe that polish matters in the overall appearance of any stone and a polish of Very Good is worth trying for.... FYI my EC has a symmetry of Good and Very Good polish.........

 

[oldminer]

Every aspect of a diamond "counts". How much is up for grabs. We just can''t generalize and say everything is of equal importance. I think a diamond graded "Good" for pol and sym is generally of simiilar potential to those graded EX and VG. However, when a cutter takes the time to do the job carefully it likely is a better overall diamond. It just makes economic sense to spend more time on more valuable material. Possibly scintillation comes down a tad with "good", but I sure can''t verify that as a fact.

The Asscher is a great example of another sort. These are square cuts. The same material used for round diamonds. They also command a nice premium for a deeply cut stone. Cutters take more time to finish a valuable item. Besides, with so few facets, the polish may be more eye visible and symmetry will become problematic if it is off cause you will see it. This particular cut is a carefully cut product.....

 

[diamondsbylauren]

Personally, I have found too many GORGEOUS fancy shapes with "Good" polish and symmetry ( merely?) to dismiss any diamond simply becasue it only got Good on polish or symmetry.

I''ve seen stones with "Fair" symmetry, but never a "fair" polish

Ana- I''d bet that storm could not tell the difference between a well cut diamond with Good polish symmetry from a diamond that''s Ex/Ex- I don''t believe I could. Dave Atlas- do you feel you could pick out a Fancy Shape diamond which was good/good, versus one which was Ex/Ex?

 

[valeria101]

Date: 9/23/2005 4:16:46 PM
Author: diamondsbylauren


Ana- I'd bet that storm could not tell the difference between a well cut diamond with Good polish symmetry from a diamond that's Ex/Ex- I don't believe I could.

I am not betting by principle... Just give me a good binocular microcope and maybe I'd be good for that bit of work - below 30x not a chance. It has been a while since I tried though

Honestly I am left with a puzzle about that polish grade. Would you care to take a look at this, David?

Let me see if I can explain what it this about:

#1. I know that the difference between 'good' and 'excellent' is most likely due to a 'localized detail' somewhere (a microscopic scratch, or a slightly rough bit of facets... stuff like that) not the overall quality of the polish like, say, 'good' polish would be grainier overall and make the whole stone less transparent.

#2. some diamonds appear more 'transparent' in a way. The sort of stuff that would make a old world jaded jeweler call one particular colorless diamond of a pile 'a great gem' when eavery other would have caused mere mortals' jaws to hit the desk anyway.

Not that I get to sort through piles of colorless diamonds every day (it only happened a couple of times), but I keep hearing this and tend to believe there is some fact of nature in the background. Unless it is an ancient diamantaire's myth

I also happen to suspect that Windowshopper here is the proud owner of an exceptional diamond like that and it is not the polish, but the quality of the crystal that makes her gem along with few others particularly endearing.


PS:
Hope you do not mind the mention, Windowshopper... otherwise, please let me know and this post goes bust asap.

 

[windowshopper]

Date: 9/23/2005 4:42:12 PM
Author: valeria101

Date: 9/23/2005 4:16:46 PM
Author: diamondsbylauren


Ana- I''d bet that storm could not tell the difference between a well cut diamond with Good polish symmetry from a diamond that''s Ex/Ex- I don''t believe I could.

I am not betting by principle... Just give me a good binocular microcope and maybe I''d be good for that bit of work - below 30x not a chance. It has been a while since I tried though

Honestly I am left with a puzzle about that polish grade. Would you care to take a look at this, David?

Let me see if I can explain what it this about:

#1. I know that the difference between ''good'' and ''excellent'' is most likely due to a ''localized detail'' somewhere (a microscopic scratch, or a slightly rough bit of facets... stuff like that) not the overall quality of the polish like, say, ''good'' polish would be grainier overall and make the whole stone less transparent.

#2. some diamonds appear more ''transparent'' in a way. The sort of stuff that would make a old world jaded jeweler call one particular colorless diamond of a pile ''a great gem'' when eavery other would have caused mere mortals'' jaws to hit the desk anyway.

Not that I get to sort through piles of colorless diamonds every day (it only happened a couple of times), but I keep hearing this and tend to believe there is some fact of nature in the background. Unless it is an ancient diamantaire''s myth

I also happen to suspect that Windowshopper here is the proud owner of an exceptional diamond like that and it is not the polish, but the quality of the crystal that makes her gem along with few others particularly endearing.


PS:
Hope you do not mind the mention, Windowshopper... otherwise, please let me know and this post goes bust asap.

of course not---------nice job Dave.................as I said I am NO expert

 

[strmrdr]

Date: 9/23/2005 1:02:42 PM
Author: oldminer

The Asscher is a great example of another sort. These are square cuts. The same material used for round diamonds. They also command a nice premium for a deeply cut stone. Cutters take more time to finish a valuable item. Besides, with so few facets, the polish may be more eye visible and symmetry will become problematic if it is off cause you will see it. This particular cut is a carefully cut product.....

That would tend to agree with my own limited observations.
If the meet points are off there is often a reason such as bad angles which show up very quickly in the pattern.

This answers Val and David also,
From what Iv seen both virtual and real life the cutters cutting the best asschers today are the ones targeting vg/vg or better.
They take the time to do it right.
Can an good asscher be cut good/good. Yes I think so but it would be rare in todays market and there might be some slight visible difference between it and one thats vg/vg but without a study of several hundred asschers min. I cant say for sure.

 

[oldminer]

I would think that in most cases I could not discern Good from Excellent in polsih or symmetry without a 10X loupe or possibly even a binocular microscope. That does not mean that I might see something occasionally that is a clue that there may be some assymmetry because a faulty shaped outline is something one can see with the naked eye. Polish is a bit tougher to see without magnification in the Good to Exc range.

I, too, would not reject a diamond based on a Good/Good versus Exc/Exc except if I was hunting for a super fine overall diamond, or unless a client was demanding that kind of perfection for their private reasons. I feel we frequently make reasonable compromises. This is certainly one of them we need to consider.

 

[acgirl]

Thank you to everyone for all of the information. I think, based on what I''ve read here, that the proof will be in looking at some stones and comparing the different types of polish and symmetry to see what I like. I have a feeling that good/good will look lovely to my eye. This was an interesting thread, and you all have given me a lot to think about.

Sometimes I think it''s easier to covet a RB just because you know if you buy ACA, or AGSO, or Ideal it is going to be a stunning looking stone. I think it can be more difficult with the fancy cut stones. However, I love the oval cut so much that I''m willing to learn as much as I can, and then look at as many as I can until I find the one that speaks to me.