GIA Exellence Polish and Symmetry

[Tim]

I understand that you need depth, table and the angles to determine whether a stone is a exellence/ideal cut.

But is it fair to say that *MOST* GIA exellence polish and symmetry stones have exellence/ideal cuts based on the fact that, exellence polish and symmetry disclose the care with which the cutters have crafted the diamond.

My question is - Is it possible to have a badly cut stone that have exellence polish and symmetry? If yes, then is fair to say that there are ideal cut stones that have poor polish and symmetry?

Would the experts on this forum please comment on this base on your experience with EX/EX GIA stones.

Thank you,

Tim

 

[Garry H (Cut Nut)]

No
Nor can you say that a diamond with VG or plain Good can not look better than an EX EX.

I have an example of a good symmetry GIA with H&A's in my stock.

 

[mike04456]

Polish and symmetry have little or nothing to do with proportions. In many cases there may be a correlation between the finish and the proportions simply because, as you noted, the cutter is taking extra effort to make the stone look good. However, as has been said many times, not all stones can be given excellent or even very good polish/symmetry because of peculiarities of the crystal.

A stone has to be a real dog to get a "poor" finish rating, but I would say it's certainly possible to get it with an ideal-cut stone. On the other hand, having EX/EX for finish says nothing about the quality of the proportions.

 

[Tim]

Thanks CutNut & Lawgem.

I guess without the HCA, it would be very hard for the average consumer to determine whether a diamond is an ideal cut by looking at the GIA certificate.

Tim

 

[diamondsman]

The answer to your questions is no!,There is no such thing as a bad cut diamond,if the certificate reads polish:ex. sym:ex.if the sym would not read ex. there might be a possibility that the stone is not symmetrically perfect!

it is very hard to get the ex-ex grade from g.i.a,a.g.s.
as they are not lieneint about it at all.

if you are planning on purchasing, and going with ex;ex,ideal cut just go for it!!

 

[Tim]

"...There is no such thing as a bad cut diamond if the certificate reads polish:ex. sym:ex..."

Thank you for your opinion Diamondsman. However, I am now confused. I was told by LawGem that POLISH and SYMMETRY has nothing to do with PROPORTIONS. Now, I am told that if the certificate reads EX/EX, the diamonds must be at least decent because "GIA and AGS are not very lienient about it"

If the proportions are out of ideal range, can a diamond get EX/EX for polish and symmetry from GIA?

Tim

 

[Garry H (Cut Nut)]

I have no idea what he means.
Ex Ex does not relate to proportions except that the crown will be between 29 degrees and 37.

 

[Richard Sherwood]

I agree. Polish and symmetry relates to the FINISH of the diamond, and has nothing to do with the proportions.

As pointed out though, an ex/ex finish shows the diamond cutter took extra care finishing up the job. Usually they don't bother doing that with what they consider poorly proportioned stones.

 

[Garry H (Cut Nut)]

Hey Rich here is one of those deep and meaningful Aussie questions

How many diamond cutters would cut EX EX if there was no one offerring a Sym and Polish grading service?

Next....


What if there was a different method of grading symmetry and as many as 1/3rd of the current grades were wrong????


What if?


u erhd it ere 1st

 

[trichrome]

Cut,

for example, the diamond I bought for my f a while ago has
an H&A pattern with G/VG P&S. and it`s a midpointer (.84) with VG proportions....
so the cutter was not trying to maximize weight since the diamond was far from being a .90....
but was looking for great proportions.... and I got that stone at 30% back Rap (because
of a 60 table).

Trichrome.