importance of Polish and Sym.

[hair guru]

I''ve just been told that you can''t tell the difference from a very good polish or sym to an excellent grade without a microscope...true or false?

 

[stone-cold11]

True

 

[Dreamer_D]

To the untrained eye anything good and above looks the same.

 

[Lorelei]

Date: 12/10/2009 4:55:36 PM
Author: dreamer_dachsie
To the untrained eye anything good and above looks the same.

Ditto, the naked untrained eye cannot normally tell the difference.

 

[oldminer]

For the perfectionist, there is a "difference" between Very Good and Excellent in polish or symmetry. In the diamond market, there is a difference between these minor features in the final asking price most of the time. There isn''t a huge gap in price differential, but it is a part of the market''s logic of bid and asked pricing.

Near colorless diamonds are graded in their top three or four best quality grades with categories where no visible difference to most folks exist without a microscope. Sure, experts have the experienced eyes and the tools to discern these upper qualities, but there is little to no practical, visual difference for the vast majority of consumers. A few consumers are what I refer to as perfectionists. It may be cultural, or purely an individual''s personality which demands levels of quality beyond the visual aspect and the market respects this choice so long as they have a willingness to pay for their particular requirements.

When a cutter or a cutting house becomes dedicated to making AGS0, H&A, Ideal cuts, whatever you prefer to call them, they tend to really pursue the finest details in order to get the Excellent P & S grades, too. With all the added effort, they might as well go for the very top end of finish. People willing to pay for the "best" would find it hard to accept Very Good in P&S when competitors offered the same with EX/EX. It would be like buying a Mercedes with a slightly off paint job. It just would not be a popular choice.

I hope that helps you understand more about why Ex/Ex is the finish demanded even if it seems to you and many others not necessary.

 

[Rockdiamond]

If we''re talking symmetry, a trained eye may be able to see why a stone was downgraded to good, naked eye.
If we''re talking polish, there''s very few cases where the "defect" or shortfall in polish could be visible with the naked eye.
Even a trained eye would need magnification- and even then, the reason GIA downgraded may be near impossible to find.

I agree with Oldminer that in today''s market ( in round diamonds primarily) cutters MUST achieve VG or EX to be considered in the "Ideal Cut" category. Regardless if it''s possible to see naked eye.

 

[BobR]

Date: 12/11/2009 1:06:16 PM
Author: Rockdiamond
If we''re talking symmetry, a trained eye may be able to see why a stone was downgraded to good, naked eye.
If we''re talking polish, there''s very few cases where the ''defect'' or shortfall in polish could be visible with the naked eye.
Even a trained eye would need magnification- and even then, the reason GIA downgraded may be near impossible to find.

I agree with Oldminer that in today''s market ( in round diamonds primarily) cutters MUST achieve VG or EX to be considered in the ''Ideal Cut'' category. Regardless if it''s possible to see naked eye.

Not sure about AGS, but GIA will not award an excellent cut grade (round brilliant) unless both P and S are at least ''VG'', so its the grading organisation not just the marketplace, thats the driver

 

[hair guru]

This has been an eye opener since I''ve been not even looking at diamonds with less than excellent polish and sym. based on the idea that I thought you could see a difference by casually looking.

Can''t thank you folks enough for your time in explaining the real deal.

Everything in life has its price, how much are you willing to pay?

 

[Rockdiamond]

You''re welcome!!

If you have the opportunity to look at stones first hand- and you''re looking at round diamonds, I''d suggest that you make sure to see some "VG" cut grade stones.
Many people will actually prefer some VGs to other EX''s based on the visual aspects- and save some money to boot!

 

[ChunkyCushionLover]

Date: 12/11/2009 1:50:34 PM
Author: hair guru
This has been an eye opener since I''ve been not even looking at diamonds with less than excellent polish and sym. based on the idea that I thought you could see a difference by casually looking.

Can''t thank you folks enough for your time in explaining the real deal.

Everything in life has its price, how much are you willing to pay?

The problem is not in a vacuum with everything being equal with just the symmetry and/or polish changing. The larger issue is WHY was the diamond lowered to VG symmetry, which meet points didn''t line up or many other factors. While the symmetry by itself may not cause a problem there may be other issues with a VG stone or other reasons why ther cutter decided not to finish the stone to the highest polish standards.

If Ie were looking at a sarin report with two branded diamonds with the same specs, angles and measurement (this is theoretical) and just one had a different polish grade but otherwise the cutting was the same then we could not tell the difference but that is never the case so caution should be used especially in looking at rounds with VG symmetry. For Fancy shapes this is more acceptable especially for cushion cut diamonds but in round or princess cuts they should be taken into consideration and closer scrutiny placed on the stone overall if those grades are lower than Excellent. No matter what the paper says I would be requesting an Idealscope and ASET image so those two optical tests along with a photograph will trump whatever the paper says but at least looking at the finish grades should make your more critical of other things like the Crown and Pavillion Angles, Depth %, Table % and Length and Width.

 

[Lorelei]

Date: 12/11/2009 1:50:34 PM
Author: hair guru
This has been an eye opener since I've been not even looking at diamonds with less than excellent polish and sym. based on the idea that I thought you could see a difference by casually looking.

Can't thank you folks enough for your time in explaining the real deal.

Everything in life has its price, how much are you willing to pay?

These links should explain what you need to know, symmetry and polish. Also bear in mind that physical symmetry which the labs grade is not the same as optical symmetry which is the result of cutting precision resulting in a hearts and arrows pattern. Also one would not normally notice any difference between VG polish and symmetry or above in images such as Idealscope or ASET.