Proportion question...

[Starry]

How tight should proportions be? Does it vary with the size of the stone? For example, 6.80-6.86, it that too much?

 

[Paul-Antwerp]

That is a very good question, Starry, but one that is very difficult to answer.

Scientists, studying light return and light performance in diamonds, have largely disregarded this question up to now. I cannot blame them for that, since it would enter a much higher complexity into any study, and the whole subject is already extremely complex.

That is why I have to return to experience with actual stones in this respect. This also rules out many responses from fellow-Pricescopers, since most of their experience is based upon the info, delivered with most online stones, and very often, one cannot judge the tightness of proportions with the available info.

For us, it is clear that increased tightness in proportions creates higher symmetry and, very important, predictability in light return, and that it is an underestimated positive influence. In this, one should pay more attention to the pavilion, slightly less to the diameters and the crown angles.

I hope that this helps.

Live long,

 

[strmrdr]

there are 2 schools of thought on this.
1: tighter is better
2: slight variations increase scintillation

My preference is tighter is better just because its a mental thing and shows awesome workmanship some people like high color and some like high clarity and I like tightly cut diamonds.
The aren't easy to find because you are narrowing the top .1% of diamonds to the .000001% range.
When you get to my preferred range the helium scanner is the only currently available scanner capable of separating them. (but then again im a nut) :}


In all likelihood until it gets too loose it don't make a whole lot of difference.

.06 is in my acceptable range but anything over .09 id be leery of if it was being sold as a super-ideal diamond.
The reason being that the angles of the facets likely have too much variation over that point to make the super-ideal class.

As Paul stated the pavilion angles are more critical because they are the engines that drive light return.

 

[Dancing Fire]

Date: 6/21/2006 4:36:27 PM
Author: strmrdr
My preference is tighter is better just because its a mental thing and shows awesome workmanship some people like high color and some like high clarity and I like tightly cut diamonds.

agree !!!

i don''t like stones with big variations. that''s when i start to question about the craftsmenship.

 

[SSam]

What is the maximum deviation allowed for GIA and AGS?