Choice between 2 diamonds: Symmetry vs Proportions

[vanquish]

Hello

I''ve got a question to hopefully help me decide between 2 diamonds whose answer is bound to be subjective but I''m hoping that somebody here maybe able to help me with based on their expertise of dealing with diamonds every day.

The selection is essentially proportions vs symmetry. One has better proportion stats (ranking as 0.7 on HCA advisor) but only ''good'' for symmetry on GIA report which might be down to its diameter variance, whilst the other is ''excellent'' for symmetry on GIA report but is on the slightly high side for crown angle at 36 and has a HCA advisor rating of 5.9.
I''m wondering how much the ''good'' symmetry would affect the HCA advisor rating and if would be better to sacrifice the close to ideal proportions in favour of ''excellent'' symmetry?

The head to head stats (all else being equal) are
Proportion Symmetry
Diameter 6.5-6.6 6.4-6.43
Depth % 60 62.1
Table % 56 60
Symmetry Good Excellent
Crown Angle 33.5 36
Pavilion Angle 40.8 41.4
Girdle 3% thn-sl.thick 3.5% Medium to sl. thick
Crown Height% 14.5 14.5
Pavilion Depth% 43 44
Star Length% 55 55
Lower Half% 75 80
Culet None None
Cut Very Good Very Good
Polish Excellent Excellent

If you need any more info that helps, just ask.

Thanks for your help with this one!

 

[Xedoc]

The difference is most likely going to be that the better proportion diamond has more brilliance and sparkle, while the more symmetric diamond aesthetically "looks" better as far as how the facets line up in proper symmetry. All else being equal, the better proportions will look like a nicer diamond from a distance.. so I''d probably pick that one. Of course, a woman looking at an e-ring in normal daylight may be irritated that facets don''t line up in proper symmetry, so it''s a preference choice. Some GIA "Good" symmetry diamonds look very symmetric when set face-up, so at times you''ll have to compare on a diamond-to-diamond basis. Get ASET images from crown and pavillion - that''ll help determine how different the diamonds are.

 

[stone-cold11]

#1 maybe is good, need an Idealscope image as HCA will not work well with symm being off.

Drop #2.

 

[vanquish]

Wow guys, thanks very much for the help so far. It''s great to be able to bounce ideas of somebody who''s got the many variables straight in their heads! (I can line them up individually, but it''s the collective impression using all the info where I start to get confused).

Xedoc, to show my lack of knowledge, how would I go about getting ASET images? Is that a simulation tool that''s available online based upon the GIA data?

Stone-Cold11, I''d like to be able to get and idealscope image, but I won''t have access to the stone until it''s bought.....d''oh!

Any other views would be greatly appreciated. If what I''ve put up is too specific, I suppose my question about the well-proportioned stone can be summed up as how badly will the ''good'' symmetry effect what should be excellent brilliance, fire and scintillation?

Thanks again folks.

 

[glitterata]

Are those two diamonds your only choices? Couldn''t you find one that has better proportions AND better symmetry?

If those are your only two choices, take #1.

 

[D&T]

Date: 9/1/2009 3:28:17 PM
Author: glitterata
Are those two diamonds your only choices? Couldn''t you find one that has better proportions AND better symmetry?

If those are your only two choices, take #1.

agreed

 

[vanquish]

These are the 2 it''s been whittled down to after much annoyance of a trusted friend who has a direct link to the wholesalers (he is an area manager of retail stores).

I could maybe pester him one last time (even though I said the last request I gave him would be my LAST request)!

Maybe somebody could help me out prior to doing that. How much extra (either retail or wholesale) should I expect to pay if I ask him to scope out a 1.01 - 1.03 carat F colour VS2 clarity stone but change my GIA cut quality request from "Very Good" to "Excellent"?

The answer to the above will determine whether I bug him one last time!?

Thanks again! I''m feeling bad even here asking yet another question!

 

[Rockdiamond]

Vanquish- given that you are working directly with a supplier, is it possible for you to actually see the diamonds in person?

Based on my experience, it''s highly unlikely you''ll notice the "good" symmetry compared to other aspects of the cut. For example, of the two stones you''ve listed, one will appear larger to your eye- it''s got a bigger spread.
Many times that would be far more of a visual impact as compared to two stones where one is EX symmetry, and the other "Good"

I would certainly suggest looking at some stones before you downgrade size, color or clarity.

 

[Lorelei]

Date: 9/1/2009 1:32:17 PM
Author:vanquish
Hello

I've got a question to hopefully help me decide between 2 diamonds whose answer is bound to be subjective but I'm hoping that somebody here maybe able to help me with based on their expertise of dealing with diamonds every day.

Hi Vanquish

I take it you prefer expert opinions from those who do in fact see many diamonds a day rather than that of consumers?

Here is info on ASET for you

http://www.highperformancediamonds.com/index.php?page=education-performance

 

[Garry H (Cut Nut)]

Date: 9/1/2009 4:43:54 PM
Author: Rockdiamond
Vanquish- given that you are working directly with a supplier, is it possible for you to actually see the diamonds in person?

Based on my experience, it''s highly unlikely you''ll notice the ''good'' symmetry compared to other aspects of the cut. For example, of the two stones you''ve listed, one will appear larger to your eye- it''s got a bigger spread.
Many times that would be far more of a visual impact as compared to two stones where one is EX symmetry, and the other ''Good''

I would certainly suggest looking at some stones before you downgrade size, color or clarity.

I would like to add a clarification to Vanquish some old issues for you and others Vanquish.
When I formulated HCA it was in a time when there were fewer symmetrical stones around.
Today VG and excellent are a natural by product out of what were once very ordinary Indian factories.
When a stone has Good sym it is often as a result of a need to meet a targeted carat weight or other factor.

The slightly shallow stone could vary from say 35 to 32.5 crown. Or 41.3 to 40.3 pavilion. Or both.

None of those proportion combinations is as bad in appearance as the other stone at 36 41.4.

Now when both are dirty, and you can not easily see as the issue Xedoc mentioned - that the facets might not line up, which is almost all lighting environments - then the shallower stone will still out sparkle very noticeably the deep dead dog.

 

[vanquish]

Thanks for the replies, especially from Garry which I think has very well addressed which of the 2 stones is better.

A couple of questions to clarify and build on your response Garry (I don''t know how do the link your comments to this post)

You say "When I formulated HCA it was in a time when there were fewer symmetrical stones around." - Does this mean that the HCA rating of a well proportioned stone should not be massively affected by the "good" rating?

"Today VG and excellent are a natural by product out of what were once very ordinary Indian factories." - I assume this applies to cut or is this symmetry? Does this imply that the factory output is now much improved and that differences between VG and Excellent cut would be difficult to observe for a non-educated observer in ambient lighting conditions?

Ultimately, a final question would be, in terms of cut performance what would be an estimate for percentile of where the better stone with good symmetry places amongst diamonds (i.e. how much more effort would I need to invest to find a better stone)? I have looked online on a lot of sites and whilst the cut standards are sometimes promising, the proportions are not great. Effect.ively, I''m wondering if my quest for the ideal cut stone has reached a point where I''m unlikely to find anything better than the stone I''ve already found.

Thanks again, I''m sorry I didn''t start asking my questions sooner.

 

[Garry H (Cut Nut)]

Date: 9/2/2009 9:14:20 AM
Author: vanquish
Thanks for the replies, especially from Garry which I think has very well addressed which of the 2 stones is better.

A couple of questions to clarify and build on your response Garry (I don''t know how do the link your comments to this post)

You say ''When I formulated HCA it was in a time when there were fewer symmetrical stones around.'' - Does this mean that the HCA rating of a well proportioned stone should not be massively affected by the ''good'' rating? proportions are way more imortant than sym and polish has to be bad to effect most stones - and below - yes the equipment got better - the VG / EX boundary is not usually able to be seen by anyone with a naked eye, and some experts can see good sym deviations in some stones. The lab standards did not change - it is the quality of cutting in sym and polish that has been upgraded with the move from Indian out waorkers into large modern factories with tight process controls.

''Today VG and excellent are a natural by product out of what were once very ordinary Indian factories.'' - I assume this applies to cut or is this symmetry? Does this imply that the factory output is now much improved and that differences between VG and Excellent cut would be difficult to observe for a non-educated observer in ambient lighting conditions?

Ultimately, a final question would be, in terms of cut performance what would be an estimate for percentile of where the better stone with good symmetry places amongst diamonds (i.e. how much more effort would I need to invest to find a better stone)? I have looked online on a lot of sites and whilst the cut standards are sometimes promising, the proportions are not great. Effect.ively, I''m wondering if my quest for the ideal cut stone has reached a point where I''m unlikely to find anything better than the stone I''ve already found. You need an appraiser to look and answer those questions. An ideal-scope will help you if you dont want to pay for an appraiser

Thanks again, I''m sorry I didn''t start asking my questions sooner.