excellent symmetry=hearts & arrows?

[prettycat]

If a round diamond has "excellent" symmetry per GIA certificate, does it mean this stone has hearts & arrow? How about "ideal" symmetry graded by AGS? Is it a guarantee of H&A? If not, how can we tell if a stone has that pattern without ideal scope pic?

 

[stone-cold11]

Nope, the only way to tell if it is a H&A is to see the Hearts image. The vendor has to supply that.

 

[jet2ks]

Good question pc.

Symmetry grades and H&A are related, but not the same thing. Most GIA Ex and AGS0 stones are not H&A, and there are occasional diamonds that show great H&A pictures, but actually do not perform well when it comes to light performance.

H&A symmetry can only be seen and verified with a Heart and Arrows viewer. IdealScope is used to judge light performance.

 

[Paul-Antwerp]

Ditto to what stone_cold said.

Technically, you need both an Arrows- and a Hearts-pic, but in case one has the Ideal-scope, one could deduct Arrows.

In all this, it is important to understand that when relating H&A to performance, the crispness of both views is of importance.

Live long,

 

[Lorelei]

Date: 5/8/2009 10:08:11 AM
Author:prettycat
If a round diamond has 'excellent' symmetry per GIA certificate, does it mean this stone has hearts & arrow? How about 'ideal' symmetry graded by AGS? Is it a guarantee of H&A? If not, how can we tell if a stone has that pattern without ideal scope pic?

No guarantee of hearts and arrows at all, the only way to tell is with hearts images and those of arrows, so no way to tell by lab graded symmetry which is refers to the physical symmetry of the diamond. The optical symmetry is related to h&a and their precision.

This link explains lab graded symmetry

http://diamonds.pricescope.com/symm.asp

 

[prettycat]

Thanks you all! Is there a huge visual difference between H&A and non H&A? I know we usually pay a premium for a stone with that pattern. Does it worth?

 

[Lorelei]

Date: 5/8/2009 11:10:42 AM
Author: prettycat
Thanks you all! Is there a huge visual difference between H&A and non H&A? I know we usually pay a premium for a stone with that pattern. Does it worth?

This depends. The proportions are the main engines that drive light return, particularly the crown and pavilion angles. You can get a diamond which has distinct hearts and arrows yet does not have good proportions and won't be the best performer. On the other side of the coin you can find a diamond which does not show hearts or arrows which has excellent proportions and will look far more beautiful that the diamond with the h&a patterning. You can of course have your cake and eat it with some of the branded h&a diamonds such as Infinity, A Cut Above etc which have excellent proportions and h&a patterning.

Also to the casual observer, arrow patterning isn't always obvious anyway what does catch attention is the light return and sparkle of a diamond which gives it life and beauty.