New Sarin Report: What to make of off-center table percentages?

[henearly89]

As shared in previous posts, I am strongly considering this diamond.

http://www.bluenile.com/round-diamond-1-carat-or-less-ideal-cut-d-color-if-clarity_LD01029163

It scores 1.3 TIC using GIA averages and 1.1 TIC using Sarin averages. Just got the Sarin back and have no idea what to do with it. The problem is that the Sarin reveals a table which is 0.5% off-center. I''ve searched the archives and can''t find much about how much tolerance is allowable for table variance. Is 0.5% considered enough to effect the diamonds performance? Does the Sarin help or hurt the case this diamond has made?

 

[JulieN]

The GIA reports "Excellent" symmetry for this diamond, so it is fine.

0.5% is not a lot.

 

[henearly89]

I don''t really trust GIA grading on its own. I think their parameters for excellent cut diamonds are too wide. I am trying to incorporate elimination techniques using the HCA combined with the Sarin report that has been provided. 0.5% doesn''t seem like a lot, but I don''t know nearly enough to feel comfortable with this.

Expert? Anyone?

 

[JulieN]

HCA is elimination tool only, please.

Again. .5% is FINE. GIA EXCELLENT symmetry is quite good enough.

 

[henearly89]

I know. I''m begging for an Idealscope image. If they can get me an OGI/Sarin, they can get me an Idealscope. I know they won''t, but that''s my sticking point for now unless I get some sort of consensus to just buy this thing and bring it to an appraiser. I love everything about it but for lack of Idealscope.

 

[yssie]

Julie is right, you're quibbling

We're talking hundredths and thousandths of a mm distances.


Here's one from GOG that has all the info you could possibly want and then some: super-super-super ideal cut, has a stated offset of 0.4% with an error margin of two-thirds of that... these are machines, run it again and you'll get a slightly different result - that's just the nature of the beast.


Buy your own IS and have fun.


http://www.goodoldgold.com/items/1759/illustrated%20report.pdf
http://www.goodoldgold.com/diamond/1759/

 

[Garry H (Cut Nut)]

Date: 2/8/2010 4:43:02 PM
Author: JulieN
HCA is elimination tool only, please.

Totally agree

Date: 2/8/2010 4:43:02 PM
Author: JulieN
Again. .5% is FINE. GIA EXCELLENT symmetry is quite good enough.

Actually t is half that - the table tilt doubles the variance - so this appears to be between .2 and .3 degrees off. A tiny bit of dust under the table when the stone was set for polishing.

Here is an article http://www.gemology.ru/cut/english/symmetry/6.htm with a stone having much more titl and great optical symmetry