Diamond Cut quality vs Color grade on Visual appearance

[susi]

So many times I see the request...please show me your F colored stones, or I want to see your I-J colored stones and so on.

I''m always facinated with the pictures posted, but still wonder why there is so much emphasis on color grading and so much emphases on cut grading ( RB stones specifically here ) BUT not much discussion of both in the same topic or maybe I''ve missed the threads where there are?

It seems to me you can''t really talk about one without talking about the other when it comes to the visual preference of color in a round brilliant diamond.

Since color is graded ( on round brilliants ) from the back, isn''t the more important thing ( visually) or at least equally important....the cut of the stone....meaning, how much white light is returned to the eye?

Why so much emphases on the color GRADE and not, at the same time, questions about a particular stone''s CUT GRADE?? Why compare my G colored stone to your G colored stone without talking about the cut grade of each? Or even comparing your F colored stone to my H colored diamond without talking about cut?

I feel like I''m fumbling around trying to ask this question and not doing very well

I wouldn''t have believed it, but my AGS0 grade diamond ( I color grade HOF brand ) looks whiter from the top/front than my GIA graded E colored ideal cut stone ( a Lazare Kaplan ) It''s a headlight compared to the Kaplan, which, by itself is a beautiful stone ( and my favorite, by the way )

Now, the HOF is larger.....so that may affect the perception of color but, goodness, the light coming from that stone is fabulous whereas my LK stone ideal cut has less light return and does not "appear" as white to my eyes.

Has anyone else ever done a comparison like this?

 

[diamondseeker2006]

Susi, I think most of us who have been here awhile take for granted that ideal cut stones are going to face up whiter than a poorly cut stone. Many PS people who stick around do end up with ideal cut stones. So I think that is sort of a given. So color and clarity are the elements left up to personal preference. That's why there are threads based on color. No one is going to want to start a thread on "show me your average cut stones"!

It's mostly the top quality cuts that are posted on those threads.

 

[Garry H (Cut Nut)]

Excellent topic.
Attached is a light yellow, about O-P-Q round Gem Adviser.
Next is a radiant

 

[Garry H (Cut Nut)]

oops

 

[Garry H (Cut Nut)]

Date: 2/2/2008 2:57:37 PM
Author: Garry H (Cut Nut)
Excellent topic.
Attached is a light yellow, about O-P-Q round Gem Adviser.
Next is a radiant

here is the radiant

 

[strmrdr]

Mainly because its a can of worms.
With non-fancy colors the material color not the face up color is what the sale price is based on.
In my opinion a vendor telling a client a H faces up like a F is borderline fraud at the worst and sales hype at best.
It faces up like a well cut H, the color grade is the same as any other H. (within the range of the grade)

Does a well cut J hide the color better than a badly cut one, yep it does in a lot of lighting conditions but its still a J.

 

[diagem]

Date: 2/2/2008 3:57:21 PM
Author: strmrdr
Mainly because its a can of worms.
With non-fancy colors the material color not the face up color is what the sale price is based on.
In my opinion a vendor telling a client a H faces up like a F is borderline fraud at the worst and sales hype at best.
It faces up like a well cut H, the color grade is the same as any other H. (within the range of the grade)

Does a well cut J hide the color better than a badly cut one, yep it does in a lot of lighting conditions but its still a J.

Correct..., but if it looks brighter due to the specific angle combination adapted to make it face up as a "G"..., than it should command a premium over a regular colored "J" face-up!

And I think it would be fine expressing an opinion that it faces up as a "G"..., just like GIA et al express their opinion when calling the color grade!

 

[strmrdr]

Date: 2/2/2008 4:06:14 PM
Author: DiaGem

Correct..., but if it looks brighter due to the specific angle combination adapted to make it face up as a ''G''..., than it should command a premium over a regular colored ''J'' face-up!

And I think it would be fine expressing an opinion that it faces up as a ''G''..., just like GIA et al express their opinion when calling the color grade!

is that a well cut G that is facing up like a badly cut E or a badly cut G facing up like a well cut J?
see the can of worms?

There is already a large cut premium that takes the potential face up appearance improvement into account.
The stone color is still a G

 

[diagem]

Date: 2/2/2008 4:13:20 PM
Author: strmrdr

Date: 2/2/2008 4:06:14 PM
Author: DiaGem

Correct..., but if it looks brighter due to the specific angle combination adapted to make it face up as a ''G''..., than it should command a premium over a regular colored ''J'' face-up!

And I think it would be fine expressing an opinion that it faces up as a ''G''..., just like GIA et al express their opinion when calling the color grade!

is that a well cut G that is facing up like a badly cut E or a badly cut G facing up like a well cut J?
see the can of worms?

There is already a large cut premium that takes the potential face up appearance improvement into account.
The stone color is still a G

There could be a well cut G facing up as an E, and there could be a regular cut G facing up as an E too (and vise-versa)..., a lot of times these things depend on other factors than just cut...

Its also possible to have a great cut G facing up as an E or even a regular cut G facing up as an E (and vise-versa)..., where is the can of worms? The fact that a premium is being charged for a "well cut"?

So if the consumer is educated to pay a premium for a well cut vs. ordinary cut..., then there should not be an issue to pay a premium for a brighter face up appearance..., the question is..., which is worth the premium more?

Or both should?

 

[strmrdr]

Date: 2/2/2008 4:26:17 PM
Author: DiaGem
There could be a well cut G facing up as an E, and there could be a regular cut G facing up as an E too (and vise-versa)..., a lot of times these things depend on other factors than just cut...

Its also possible to have a great cut G facing up as an E or even a regular cut G facing up as an E (and vise-versa)..., where is the can of worms? The fact that a premium is being charged for a ''well cut''?

So if the consumer is educated to pay a premium for a well cut vs. ordinary cut..., then there should not be an issue to pay a premium for a brighter face up appearance..., the question is..., which is worth the premium more?

Or both should?

I dont have a problem with someone saying that a lot of people find a well cut lower color stone too be acceptable because its brightness masks color.
But when someone says it faces up like a specific color it is not correct because that is not how diamond color is graded.

 

[diagem]

Date: 2/2/2008 4:32:26 PM
Author: strmrdr

Date: 2/2/2008 4:26:17 PM
Author: DiaGem
There could be a well cut G facing up as an E, and there could be a regular cut G facing up as an E too (and vise-versa)..., a lot of times these things depend on other factors than just cut...

Its also possible to have a great cut G facing up as an E or even a regular cut G facing up as an E (and vise-versa)..., where is the can of worms? The fact that a premium is being charged for a ''well cut''?

So if the consumer is educated to pay a premium for a well cut vs. ordinary cut..., then there should not be an issue to pay a premium for a brighter face up appearance..., the question is..., which is worth the premium more?

Or both should?

I dont have a problem with someone saying that a lot of people find a well cut lower color stone too be acceptable because its brightness masks color.
But when someone says it faces up like a specific color it is not correct because that is not how diamond color is graded.

That''s not how Diamonds are graded by who??? The GIA et al???

Strmrdr..., I can vouch for my self (and some of my colleagues...)..., I (we) dont grade on table down position only!!!
To achieve a perspective of what grade we will get from GIA et al, we must act like them..., but believe me when I purchase rough Diamond material I sometimes dont even know where the table will be...

 

[strmrdr]

Date: 2/2/2008 4:45:00 PM
Author: DiaGem
That''s not how Diamonds are graded by who??? The GIA et al???

Strmrdr..., I can vouch for my self (and some of my colleagues...)..., I (we) dont grade on table down position only!!!
To achieve a perspective of what grade we will get from GIA et al, we must act like them..., but believe me when I purchase rough Diamond material I sometimes dont even know where the table will be...

like it or not from a consumers perspective how GIA and other labs grade them is what the selling price is based on.
Buying rough is a whole nuther ball game and you can grade them in anyway that works for you :}

 

[diagem]

Date: 2/2/2008 4:55:29 PM
Author: strmrdr

Date: 2/2/2008 4:45:00 PM
Author: DiaGem
That''s not how Diamonds are graded by who??? The GIA et al???

Strmrdr..., I can vouch for my self (and some of my colleagues...)..., I (we) dont grade on table down position only!!!
To achieve a perspective of what grade we will get from GIA et al, we must act like them..., but believe me when I purchase rough Diamond material I sometimes dont even know where the table will be...

like it or not from a consumers perspective how GIA and other labs grade them is what the selling price is based on.
Buying rough is a whole nuther ball game and you can grade them in anyway that works for you :}

You are right..., except the premium a consumer would have to pay for an I graded Diamond which faces up like an G...

(not quite as high as a graded G but could be substantial higher than a regular tinted I colored appearance...)

Which is not calculated the same as a EX-EX cut which the GIA et al identify on their reports and then naturally command premiums!!!

See what I mean

 

[coatimundi_org]

Date: 2/2/2008 5:05:46 PM
Author: DiaGem

Date: 2/2/2008 4:55:29 PM

Author: strmrdr

Date: 2/2/2008 4:45:00 PM

Author: DiaGem

That's not how Diamonds are graded by who??? The GIA et al???


Strmrdr..., I can vouch for my self (and some of my colleagues...)..., I (we) dont grade on table down position only!!!

To achieve a perspective of what grade we will get from GIA et al, we must act like them..., but believe me when I purchase rough Diamond material I sometimes dont even know where the table will be...

like it or not from a consumers perspective how GIA and other labs grade them is what the selling price is based on.

Buying rough is a whole nuther ball game and you can grade them in anyway that works for you :}

You are right..., except the premium a consumer would have to pay for an I graded Diamond which faces up like an G...

(not quite as high as a graded G but could be substantial higher than a regular tinted I colored appearance...)


Which is not calculated the same as a EX-EX cut which the GIA et al identify on their reports and then naturally command premiums!!!


See what I mean

Hello,
I just bought a K color RB that faces up whiter than my G oval (in certain lighting conditions, of course), and I'm certainly glad I didn't have to pay a premium for a K that faces up whiter than it's actual grade!

 

[Allison D.]

Susi, I think the reason you hear so many questions about color (and few about cut grade) is more a function of marketing by large retailers.

In those large retailers, the salespeople tend to harp on color (and to a lesser extent clarity), so when people come here to Pricescope, the only thing most of them know enough to ask about is color. Since they aren''t being given information in those stores about cut (meaning how well the stone is cut, not the shape), they don''t even know to ask. That''s really why Pricescope has been so helpful; in many cases, this is the first place they''ll hear that cut is the thing that makes a diamond sparkle.

 

[Allison D.]

I think it''s important to keep in mind color grade isn''t a factual thing; it''s subjective. Grading is either a lab''s opinion or an individual''s educated opinion about the color of the stone. It''s not a factual piece of data. Diamonds don''t have inherent color labels.

It would be factual, though, to say that a diamond is a GIA-graded G. The color grade varies depending on whose grading system you use.

 

[Regular Guy]

Not sure...I''ve read the many posts following Susi''s query in this thread.

It seems like you can go off in any of several directions with part of the original question...but all of these comments just go from the stated juxtaposition of ideas (color connected with cut). But, regarding the actuals of her observations, going back to her final assessment:

Date: 2/2/2008 2:40:13 PM
Author:susi

I wouldn''t have believed it, but my AGS0 grade diamond ( I color grade HOF brand ) looks whiter from the top/front than my GIA graded E colored ideal cut stone ( a Lazare Kaplan ) It''s a headlight compared to the Kaplan, which, by itself is a beautiful stone ( and my favorite, by the way )

Now, the HOF is larger.....so that may affect the perception of color but, goodness, the light coming from that stone is fabulous whereas my LK stone ideal cut has less light return and does not ''appear'' as white to my eyes.

Has anyone else ever done a comparison like this?

I don''t know on what basis Susi would find the differential she does. Both HOF and Lazare are primo makes. At least I think Lazare reliably is. To confound this further, Suzi mentions the Lazare is her favorite, too (sentimentally?), and the actual color differential is I vs E. Further...if the colors were reversed...I might have had a supposition...with the larger stone holding more of the color, and being seen more for its color. But that''s not the case here.

 

[Garry H (Cut Nut)]

In this image I took the round file i posted above, made it shallower to increase the light return / shorten the ray path''s, and painted it quite a bit (ala Eightstar who once messed about and destroyed the color potential of some fancy rough). The rsult is an even less coloured variance.
beside it is the radiant file I posted above.
The color of each sample is the same from an asorbption spectrum file with the following absorption.

Not just how dramatic the effect on color caused by cut.
The question is, should labs take this into account, or just do the body color thing?
IGI does to some extant, and all labs do on fancy color grades - but maybe it is time to do it for face up colours too?

370 0.573
371 0.585
372 0.604
373 0.623
374 0.641
375 0.656
376 0.665
377 0.673
378 0.677
379 0.674
380 0.696
381 0.709
382 0.729
383 0.745
384 0.789
385 0.730
386 0.718
387 0.699
388 0.686
389 0.680
390 0.684
391 0.692
392 0.700
393 0.709
394 0.727
395 0.719
396 0.680
397 0.624
398 0.580
399 0.561
400 0.558
401 0.571
402 0.601
403 0.627
404 0.610
405 0.559
406 0.486
407 0.402
408 0.361
409 0.341
410 0.320
411 0.298
412 0.282
413 0.286
414 0.360
415 0.601
416 0.417
417 0.229
418 0.169
419 0.142
420 0.125
421 0.110
422 0.098
423 0.088
424 0.082
425 0.079
426 0.076
427 0.073
428 0.068
429 0.064
430 0.059
431 0.056
432 0.053
433 0.051
434 0.050
435 0.049
436 0.049
437 0.049
438 0.049
439 0.048
440 0.048
441 0.047
442 0.046
443 0.046
444 0.045
445 0.045
446 0.045
447 0.045
448 0.046
449 0.048
450 0.049
451 0.050
452 0.050
453 0.050
454 0.049
455 0.047
456 0.046
457 0.045
458 0.044
459 0.044
460 0.044
461 0.044
462 0.044
463 0.044
464 0.044
465 0.043
466 0.043
467 0.042
468 0.041
469 0.040

 

[strmrdr]

Date: 2/2/2008 11:39:50 PM
Author: Regular Guy
Not sure...I've read the many posts following Susi's query in this thread.

It seems like you can go off in any of several directions with part of the original question...but all of these comments just go from the stated juxtaposition of ideas (color connected with cut). But, regarding the actuals of her observations, going back to her final assessment:

Date: 2/2/2008 2:40:13 PM
Author:susi

I wouldn't have believed it, but my AGS0 grade diamond ( I color grade HOF brand ) looks whiter from the top/front than my GIA graded E colored ideal cut stone ( a Lazare Kaplan ) It's a headlight compared to the Kaplan, which, by itself is a beautiful stone ( and my favorite, by the way )

Now, the HOF is larger.....so that may affect the perception of color but, goodness, the light coming from that stone is fabulous whereas my LK stone ideal cut has less light return and does not 'appear' as white to my eyes.

Has anyone else ever done a comparison like this?

I don't know on what basis Susi would find the differential she does. Both HOF and Lazare are primo makes. At least I think Lazare reliably is. To confound this further, Suzi mentions the Lazare is her favorite, too (sentimentally?), and the actual color differential is I vs E. Further...if the colors were reversed...I might have had a supposition...with the larger stone holding more of the color, and being seen more for its color. But that's not the case here.

yea good point...
but thats the brightness not the color, change the lighing and that will change too,
c/p combo and short/vs long lgf% can change the way it handles light in different lighting.
For example 41/34 will be more directional than a 35.5/40.6 and a 75% lgf% may be more effected by the head shadow present than 80%.
Sounds like that is the issue more than face up color vs actual color comparing those 2 stones.

edit: also LK was king of the old school 60/60s for a long time it may not even be comparing apples too apples.

 

[diagem]

Date: 2/2/2008 11:47:48 PM
Author: Garry H (Cut Nut)
In this image I took the round file i posted above, made it shallower to increase the light return / shorten the ray path''s, and painted it quite a bit (ala Eightstar who once messed about and destroyed the color potential of some fancy rough). The rsult is an even less coloured variance.
beside it is the radiant file I posted above.
The color of each sample is the same from an asorbption spectrum file with the following absorption.

Not just how dramatic the effect on color caused by cut.
The question is, should labs take this into account, or just do the body color thing?
IGI does to some extant, and all labs do on fancy color grades - but maybe it is time to do it for face up colours too?

Too..., thats the key

, not only as they do fancy colors...

I think this should be "elementary my dear"

I also think Diamonds should be graded based on a few lighting environments..., not only in one "boxed"

 

[strmrdr]

Date: 2/3/2008 1:00:26 AM
Author: DiaGem
Too..., thats the key

, not only as they do fancy colors...

I think this should be ''elementary my dear''

I also think Diamonds should be graded based on a few lighting environments..., not only in one ''boxed''

no way that would make color grading a worse mess than it is now and even more subjective.
Trying to get a accurate and repeatable grading system in multiple lighting using human graders would be a mess beyond belief.

 

[diagem]

Date: 2/3/2008 1:12:20 AM
Author: strmrdr

Date: 2/3/2008 1:00:26 AM
Author: DiaGem
Too..., thats the key

, not only as they do fancy colors...

I think this should be ''elementary my dear''

I also think Diamonds should be graded based on a few lighting environments..., not only in one ''boxed''

no way that would make color grading a worse mess than it is now and even more subjective.
Trying to get a accurate and repeatable grading system in multiple lighting using human graders would be a mess beyond belief.

Strmrdr,

Didnt you notice it looks like Diamond commoditization is not doing to well on taking off....

Add the fact that there are no two Diamonds alike..., equals = SUBJECTIVITY!!!

Please dont be shocked from my next opinion...

I think subjectivity is slowly making a come-back in the Diamond field...