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Polish and Symmetry revisited

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Babylon1023

Rough_Rock
Joined
May 28, 2002
Messages
54
I know this subject was brought up before, but I don't think any clear answer was reached. I only ask this again because during my research I've gotten a few conflicting answers and I want to run it by again to be sure.

Now, just in terms of what a novice can notice with his/her naked eye, is there ANY noticable difference between the Excellent/Ideal, Very Good, and Good cut grades in either the polish or symmetry category? Are ALL the differences just under a microscope, or is there a difference you can notice just by looking at it? We all want our women to have the brightest, shiniest, and most firey thing we can buy, but in the interest of all the budget buyers here I want to settle this once and for all.

Put it this way, would ANY of these diamonds look different, all things being equal (assume an Ideal cut) ?

Polish/Symmetry:
-Very Good/Very Good
-Very Good/Good
-Good/Very Good
-Good/Good

In terms of what you can notice with the naked eye (novicewise), are any of the above combinations to be avoided? Would they all look the same? Is either polish or symmetry more important than the other? If possible, I'd love to get Very Good in both categories, but if I had to settle with a Good rating on one or both of the categories, which one should it be (or would a demotion in either one negatively impact the visual quality)? I'm sorry to be reiterative, but I'm sure that's what a lot of novice budget buyers are pondering right now, and I think it would help us out a lot to get some good advice from the experienced here.

Thanks!!
 

Caratz

Shiny_Rock
Joined
Jun 4, 2002
Messages
222
If the symmetry is off you will be able to tell if you look straight into the table. Lack of symmetry makes very little difference when it comes to light return, fire, etc. It only makes a difference if you want to see a symmetrical pattern.

I am a novice and I cannot tell the difference between good polish and excellent polish.

Symmetry matters to me. Polish does not.
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
I agree with Caratz.

: "Rarely is the polish of diamond so bad that it mars the beauty of a diamond. Only be concerned if the polish is rated as poor."

Symmetry is something you might appreciate.[/u]
 

jamesd

Shiny_Rock
Joined
Feb 8, 2001
Messages
106
If it is H&A the you know the facets are consistent enough. Doesn't matter much whether two points line up perfectly so much as the body of those facets being at the right angles.
 

Babylon1023

Rough_Rock
Joined
May 28, 2002
Messages
54
So you guys are saying there is no noticable difference between Very Good/Very Good Polish/Sym and that I should only be concerned if either rating is below good? That's great b/c a few of the diamonds I've seen have only Good/Good ratings, but I take it there's nothing wrong with that unless I'm whipping out a loupe. Thanks!
 

pricescope

Ideal_Rock
Joined
Dec 31, 1999
Messages
8,266
I just wanted to say that you shouldn't worry about polish - Good is good enough :)

Symmetry is less important than crown and pavilion angles. See Ideal-Scope - Symmetry

However, overage crown and pavilion angles can be misleading symmetry is low.

At this point you should look at the diamond yourself or with an expert. Or use ideal-scope.

Buying diamond with ideal proportions and ideal symmetry is some sort of guarantee.

From Cut Nut new tutorial:

"The biggest problem encountered with good to fair symmetry results when locally steep crown facets are aligned directly above deep pavilion facets, but the odds do not favour of this situation. A more likely situation is one area of a diamond will leak slightly as a result of a crown angle variation of one or two degrees. The Ideal-Scope easily detects this problem.

Perhaps the most important reason to select a stone under 1 rather than under 2 is diamonds with higher HCA scores will suffer more from poor symmetry. If the scores are very low then variations in angles that result from poor symmetry are less critical.

You may never notice any difference between diamonds graded ideal or excellent and good symmetry unless they are larger than one carat.

The Ideal-Scope is the most effective measure of symmetry because the patterns we observe with it display ‘optical’ symmetry. For the purist who demands perfect symmetry, consider Hearts and Arrows."
 

Babylon1023

Rough_Rock
Joined
May 28, 2002
Messages
54
I see,

So you're saying that while I'll never notice a difference between Very Good and Good Polish, I should strive to get at least Very Good symmetry to avoid problems.

Thanks!
 

Babylon1023

Rough_Rock
Joined
May 28, 2002
Messages
54
Here's the response I just got from Tricia at Blue Nile, I thought I'd share it:

"The difference between Very Good and Good
Symmetry and Polish is not something that can be seen with the naked eye.
If you had one diamond with Good Symmetry and Polish and one with Ideal
or Excellent symmetry and polish next to each other and they had the
same depth and table percentages and color etc, even then you would not
be able to see a difference, though if you knew which was which and you
spent a long time looking back and forth, you may be able to convince
yourself otherwise. Some people's eyes are more sensitive than others. I
for myself would feel just fine with Good Symmetry and Polish and Ideal
Depth and Table Percentages."
 

lawmax

Brilliant_Rock
Joined
Dec 31, 1999
Messages
1,317
You have to remember that there is a difference between optical symmetry and the kind of symmetry (external meet-point faceting) that is graded by the labs. Experts will tell you that, with the naked eye, you can't tell excellent from good as graded by the labs.
 
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