Cut and Clarity - resulting brilliance/fire

[BlingChaser]

I''ve been reading up on various websites about the 4 C''s and about how the most underrated/elusive C is the cut.

In many previous blogs, it has been mentioned that the quality of Cut dictates how much fire/scintillation/life a stone displays and this totally makes senise as these would depend on light return which in turn depends on angles and hence on Cut.

But my question is this, in an extremely well cut diamond would the inclusions ( say SI1, SI2) not deflect a lot of light from hitting the right facets and hence affect the scintillation of the diamond?

In the same vein, i was wondering which stone would be better assuming color being the same:

1. Ideal Cut SI2
2. Premium Cut VS2

 

[Regular Guy]

Though you''ll want a more informed opinion than mine, on purely the properties of light, generally, I''d opt for the ideal cut, given these two choices. Usually, though, there are separately potential objections to the potential inclusions themselves in an SI2, that makes those options more challenging, independent of the inclusion''s effect of light performance, per se.

Dave Atlas has provided warnings to consumers about the potential effect of inclusions, but I don''t think I''ve seen any real examples provided to back up this concern. Then again, each diamond is really a singleton, and unless some sort of systematic method were used, it''s not exactly clear what system you''d use to document what you''re asking, if evidence of the concern was to be sought for.

 

[diamondseeker2006]

Too many variables unknown. I''d rather have an ideal cut SI1 over either of those. An SI2 may or may not be eye clean, and I wouldn''t want a premium cut.

 

[decodelighted]

All inclusions are not equal. You can''t really generalize like that I''m afraid. Some inclusions are WHITE (and much less obvious) ... some fall in the part of a stone that can be covered by a prong & never seen once it''s in a ring.

An Si2 with a black inclusion in the center ... how can that be comperable to an Si2 with a white feather that''s "prongable"?

It also depends on the type of cut/shape you''re getting ... ROUNDS and RADIENTS and PRINCESSES hide inclusions a lot better than EMERALDS or ASSCHERS.

You should talk to the vendors about the stones & see where the inclusions are and how noticable ("eye clean") the stones are .. and from what distance.

Generally folks around here will always direct you to IDEAL cut stones ... but that brings up the questions, who''s definition of "ideal" is it. The vendor? Is the stone a true Hearts & Arrows? An AGS 000??

 

[Paul-Antwerp]

Take the extreme case of an I2, and consider how much of the surface area would be touched by the inclusion. Of course, it is difficult to measure, and it depends upon the stone, but my guess would be maximum 5%.

I think that even in this clarity, a better cut-quality will still be giving a higher light performance.

So, therefore, in the case of an SI2, which I estimate will not even have an effect on 1% of the surface area of the stone, cut-quality will clearly prevail.

Live long,

 

[Lorelei]

Welcome

Usually a diamond needs to be very included ( i2 or I3 ) for those inclusions to interfere with the passage of light and therefore performance. SI1 and SI2 can be eyeclean clarity grades and not affected by this, as indeed can be some I1's. Also even if a diamond is not eyeclean it can still sparkle and not have the performance affected by a visible inclusion. The exception if I remember rightly, is if an SI2 for example has the grade setting inclusion of being clouds which can make the diamond lack brilliance.

With the labelled ideal Cut, Premium Cut grades, it isn't as easy as that to judge cut! These labels don't always mean much or if a diamond is well cut at all, each diamond must be evaluated on it's proportions and how well these work together. Too many variables to judge here.

 

[chrono]

BC,

I presume the vendor is the one giving the tags "ideal cut" and "premium cut"? I would not take them at their word because I don''t know their criteria for those cuts. Do you have the following cut information?

Shape of diamond
Depth and Height
Crown and Pavilon angles
Girdle thickness
Polish and Symmetry information
Type and Location of inclusion(s) for the SI2

Once we have that information (or Sarin report or Idealscope picture), can the PS regulars give their opinion why one diamond would sparkle better than the other.

 

[BlingChaser]

Thanks for all your feedback.

The round diamond in question i had seen was an ideal cut as per the AGS standards with all the params (Depth, Height, Crown, pavillion and girdle) falling within the "ideal' range and being an SI2 GIA graded diamond. Color was very good at E. I plugged in the numbers in the HCA caculator and it came back with 0.9.

To my untrained eye, i could not see the inclusions unaided. But once i used the Loupe, i could see the inclusions with 1 black inclusion towards the perimeter of the table and small cluster of inclusions around the edge of the stone.

It was then that i started thinking about how inclusions would affect light return.

I just used example 2 as a theoretical basis to try and think about alternatives.


Thanks all for your feedback.

 

[oldminer]

We are involved in a business where the tiniest differences in grades make a lot of dollar difference. We are also in a business where the determination of these grades is still rather subjective, for the most part.

Although you may not see the difference in beauty between an SI1 and a VS1, there may be some measureable, though minute difference. It likely would not be sufficient to make you buy one or the other, but if we are speaking of measuring absolutes, there is a small incremental difference. TYhe same applies to a D color versus and E color. You buy what you like and can afford. THere is very little difference in physical appearance.

Cut, clarity and color all play a part in arriving at the "value" of a diamond. Just because you can''t see a difference does not mean there is no difference. The diamond business is based on slight gradational changes that the eyes can barely detect, if at all.

 

[BlingChaser]

Your responses have been great and will try and elaborate a bit more what the inclusions look like. I''ll try and post the inclusion locations from the certificate but the overall feel seems to be that cut should prevail unless the inclusions tend be to be clustered in the center of the table.

So far i have not thought about "Value" but sometimes i have trouble reconciling the "Value" of the diamond in terms of what i have to pay vs the "Value" which most untrained eyes would be able to place on a diamond at a cursory glance. As such i personally tend to place more weight on Carat, Cut, Color and Clarity in that order and try to stay away from "weak" extremes.

Hence the basis of my original question whether i should sacrifice Clarity for Cut.

 

[Cehrabehra]

Date: 11/7/2006 11:47:15 AM
Author:BlingChaser
I''ve been reading up on various websites about the 4 C''s and about how the most underrated/elusive C is the cut.

In many previous blogs, it has been mentioned that the quality of Cut dictates how much fire/scintillation/life a stone displays and this totally makes senise as these would depend on light return which in turn depends on angles and hence on Cut.

But my question is this, in an extremely well cut diamond would the inclusions ( say SI1, SI2) not deflect a lot of light from hitting the right facets and hence affect the scintillation of the diamond?

In the same vein, i was wondering which stone would be better assuming color being the same:

1. Ideal Cut SI2
2. Premium Cut VS2

boy - if I were going for a round cut would be PARAMOUNT to me for sure - BUT I really don''t think I could stand a SI2 for my own mind clear reasons... I''d opt for the premium cut likely - but truth be told, I''d go for the ideal vs2

 

[Lorelei]

Date: 11/7/2006 5:04:17 PM
Author: BlingChaser
Your responses have been great and will try and elaborate a bit more what the inclusions look like. I''ll try and post the inclusion locations from the certificate but the overall feel seems to be that cut should prevail unless the inclusions tend be to be clustered in the center of the table.

So far i have not thought about ''Value'' but sometimes i have trouble reconciling the ''Value'' of the diamond in terms of what i have to pay vs the ''Value'' which most untrained eyes would be able to place on a diamond at a cursory glance. As such i personally tend to place more weight on Carat, Cut, Color and Clarity in that order and try to stay away from ''weak'' extremes.

Hence the basis of my original question whether i should sacrifice Clarity for Cut.

If you put it that way, if you choose a top cut SI2 clarity which is eyeclean and doesn''t have any integrity threatening inclusions which is rare anyway in this grade, then the way I see it - apart from the " mindclean" issue that Cehra mentioned, no sacrifice needed!

To your eyes and the eyes of all who view, an eyeclean SI2 to all intents will look the same as it''s same coloured, cut and lab graded counterpart. It depends on comfort zones I think. If you would feel happier with a higher clarity, then that might be the best fit for you.