Perfection by the Numbers?

[Andelain]

Hello again,

I just want to get the opinions of some of you experts on cut. If you had to pick a perfect diamond sight unseen, strictly based on the numbers, what would you look for? I’ve been reading here and trying to expand my knowledge and wanted to find out how much I’ve learned. I trolled GOG’s site and found this and reading the specs I wondered if I’d found the closest thing to a perfect cut I could find. Please do me a favor and look at http://www.goodoldgold.com/diamond/6883/, and give me your opinion of just the cut based on the dimensions given. I’m not concerned with size, color, or clarity for right now.

Thanks all.

 

[missydebby]

oooooo, LoneW, do you have your eye on a new diamond?!?

 

[Andelain]

Date: 7/2/2010 7:34:36 PM
Author: missydebby
oooooo, LoneW, do you have your eye on a new diamond?!?

It's a pretty thing isn't it?

Although I need another diamond like I need a hole in my head. Wait, maybe I shouldn't say that over here in a war zone...

Truth is, I don't have a use for it and GOG doesn't have anything even close to matching it, so I have no idea what to do with it. But that L would be something to see. I'm really just trying to get the experts here to comment on this one strictly based on the specs. My thought is that hitting right in the center of the ideal crown/pav angles with 81% LGF lengths would make this one jump out at you. I'd also like any comments on other factors like star lengths, etc that might affect it.

Anyone willing to weigh in?

 

[Karl_K]

nothing stands out as being any kind of an issue.
It has longer lgf% as you know which is the only thing I saw to note.

 

[Andelain]

Date: 7/2/2010 9:35:30 PM
Author: Karl_K
nothing stands out as being any kind of an issue.
It has longer lgf% as you know which is the only thing I saw to note.

Karl, what''s your opinion of a longer LGF% over a normal length or even a shorter one? Do you share the opinion others have said that it makes for a brighter diamond?

Thanks

 

[stone-cold11]

No issue, just thinner arrow shafts, more splintery facets. Also the hearts image has a deeper cleft, so not qualify as a standard H&A diamond, but that is just definitions.

 

[Karl_K]

Date: 7/2/2010 10:04:34 PM
Author: Lone_Wolfe

Date: 7/2/2010 9:35:30 PM

Author: Karl_K

nothing stands out as being any kind of an issue.

It has longer lgf% as you know which is the only thing I saw to note.

Karl, what''s your opinion of a longer LGF% over a normal length or even a shorter one? Do you share the opinion others have said that it makes for a brighter diamond?


Thanks

slightly different look.
No would not say brighter, just different.

 

[Andelain]

So do you prefer them longer like this one or a bit shorter?

I guess what I''m trying to ask is if you could specify all the lengths/depths/angles of a diamond being cut, what would you choose? Designing your perfect diamond...

 

[Karl_K]

Date: 7/2/2010 11:35:48 PM
Author: Lone_Wolfe
So do you prefer them longer like this one or a bit shorter?


I guess what I''m trying to ask is if you could specify all the lengths/depths/angles of a diamond being cut, what would you choose? Designing your perfect diamond...

There is no one perfect combination.
My dream round today would likely end up pretty close to the gog oec or whatever he is calling it.
Which doesn''t help you because that is my preference today not yours :}
I am on a broad flash kick lately but that might change tomorrow to long lgf, med lgf, fic, bic who knows :}

Jon has a video where he compares the various lgf% that might help you.
I cant link it but if you cant find it someone might come along and link it.

 

[Rhino]

That's a really tight one. If you look at the Helium Report and the Octonus theory deviations of the crown and pavilion angles they are less than .1 degree deviations which is a mathematical miracle.

Look at the DiamXray exam. That level of precision involves extremely precise cutting not only in the slope angles (slope angles are those you typically see on reports and are angles cut in the north/south orientation) but also extremely precise cutting in the east/west orientation. Those angles are referred to as the azimuth angles and are equally precise. All optical testing confirms.

Longer lower girdle facets result in more reflections of the lower halves under the table which are responsible for bright reflections in that region (more reds than blues in ASET) which scrutinizing eyes can see and also results in slightly more sparkle scintillation as well. We have hd vidoes documenting the differences in appearance in my video addressing the subject of the lower half facet length. As Karl points out not an earth shattering difference but a difference nonetheless. Good eye.

Kind regards,

 

[soontomarry2]

I notice that the Isee2 results show this diamond as not having near 10 for symmetry. It rates near 10 in the other catergories. I've seen this with many of other GOG stones. Why is this? Is Isee2 downgrading the stone because of the longer lower girdle facets and the greater distance between the tip of the heart and the rest of arrow in the hearts image? (I'm assuming this longer distance is created by a longer lgf) Or is this result due to the culet not being centered under the table? More generally, how does the Isee2 system work?

 

[Andelain]

I notice that the Isee2 results show this diamond as not having near 10 for symmetry. It rates near 10 in the other catergories. I've seen this with many of other GOG stones. Why is this? Is Isee2 downgrading the stone because of the longer lower girdle facets and the greater distance between the tip of the heart and the rest of arrow in the hearts image? (I'm assuming this longer distance is created by a longer lgf) Or is this result due to the culet not being centered under the table? More generally, how does the Isee2 system work?

I'm curious how that works myself, and if other vendors use it at all.

I'm guessing that a slightly off-center culet will have more effect on the score than longer LGF's, as long as those are uniform. Maybe an expert will chime in here.

Rhino had mentioned that this stone has minimal variations in the azimuth angles shown on the helium report. Can anyone give me a link to another AGS 0 stone that has considerable more variation so I can compare the 2? I'm not concerned about size, color, clarity, or vendor as long as I can see the report, IS and a pic. It can be a stone that's already sold.

 

[soontomarry2]

I'm curious how that works myself, and if other vendors use it at all.

I'm guessing that a slightly off-center culet will have more effect on the score than longer LGF's, as long as those are uniform. Maybe an expert will chime in here.

Paging Dr. Rhino?

 

[Rhino]

Apologies for not seeing this sooner.

Regarding whehter an off centered culet or longer lgf's would affect the diamond, the off centered culet would most likely.

The Isee2 is the only digital optical examination that scrutinizes "Optical Symmetry" and the intensity/consistency of the bright/dark reflections in a controlled environment so if there are deviations in either the patterning of the diaimond or the intensity at which it reflects light back we'd see it in the results.

 

[Andelain]

Apologies for not seeing this sooner.

Regarding whehter an off centered culet or longer lgf's would affect the diamond, the off centered culet would most likely.

The Isee2 is the only digital optical examination that scrutinizes "Optical Symmetry" and the intensity/consistency of the bright/dark reflections in a controlled environment so if there are deviations in either the patterning of the diaimond or the intensity at which it reflects light back we'd see it in the results.

So, if I understand you correctly is it possible for anything else such as inclusions to affect the score on this test? For example, let's say hypothetically I had a stone that had every facet, angle, azimuth cut perfectly and symmetrically but the stone had a decent sized feather or cloud just off the table. SI-1 or 2 sized. Could that block enough light in one area to lower the score?