Brainstorming new innovative Diamond grading ideas:

[diagem]

We started discussing this subject on the "AGS introduces cut grading on DQR reports" thread...

https://www.pricescope.com/community/threads/ags-introduces-cut-grading-on-dqr-reports.97120/page-11

I thought this issue deserves a new thread of its own + I didnt want to mix with the importance of the other thread....




Serg..., you have good ideas and good intentions for re vamping (perhaps) the Diamond grading systems which are (and were) used for decades...
I believe you are correct..., and as innovations are constantly born in our Diamond industry..., from rough marketing to cutting and not to mention polished marketing..., I believe grading should also be changed (or re-sharpened) to meet these fast changes our industry is going through....

Any ideas and thoughts welcome:

Serge wrote:

RE>>> Date: 11/8/2008 5:09:58 AM
Author: Serg

"We have different goals.
For example
1) You ask reject ASG Gold
2) AGSL has goal to increase market niche

If market just reject AGS gold or if AGSL recall( hard to believe) AGS Gold, it can not increase current market AGSL niche( My point what AGS Gold Could decrease AGSL niche, I am agree what AGS Gold could increase AGSL niche. It is hard to predict. I am feel what it is strategically wrong step for AGSL because AGS Gold is step back and very contradictive with AGS Platinum )

It is not so constructive to ask just reject AGS GOLD.

I am trying show good commercial perspective to develop cut grading system according future market demands. It is best way to increase market niche for AGSL

1) Real consumer Education.
a. Open discussions with Labs
b. Consumer connoisseur groups
c. Use marketing strategy from Vine market
2) Fancy cuts , 3D light performance grade with Same rules for all cuts
a. Grading for Cutter Houses Brands
b. Score for Luxury Brands diamond.( MontBlanc , Louis Vuitton, Tiffany, Escada ,)
3) Grading the facet flatness . I think it is very important for brilliancy and fire. Most probably what H&A diamonds are more bright due better facet flatness .Good flatness is much more important for optics than smoothing.
4) Milkyness( transparency )
5) Color grade from table( for colorless diamonds)
6) Objective clarity grade( Full 3D model with 3D inclusions .)
a. It will help change diamond stock to sempolish stock and work according orders like in other industries ( usually you order car for your specific demands: color, music, motor, leather upholstery,..)
7) Objective color grade for color fancy diamonds( I remember answer and reason)

Sergey Sivovolenko
CEO OctoNus"

 

[diagem]

RE>> "Date: 11/8/2008 12:16:02 PM
Author: Serg

Diagem,

Re: How do you score (or market) Dia cuts that are based on other factors of beauty (where Brilliance/Scint/Fire is of less importance)?

I have not any agenda to score Shape, Pattern ,..


For example main current difference between MontBlanc and Louis Vuitton cuts is shape( according to Brand Logo)
But scores of Brilliance/Scint/Fire are important for promotion and consumer selection Brands between MontBlanc and Louis Vuitton.

You use same scores to select car for you. but you use other motivation too. Its not contradictive . It is Help do best selection for you and spend minimum time "

 

[diagem]

Date: 11/8/2008 12:43:39 PM
Author: DiaGem



RE>> ''Date: 11/8/2008 12:16:02 PM
Author: Serg

Diagem,

Re: How do you score (or market) Dia cuts that are based on other factors of beauty (where Brilliance/Scint/Fire is of less importance)?

I have not any agenda to score Shape, Pattern ,..




For example main current difference between MontBlanc and Louis Vuitton cuts is shape( according to Brand Logo)
But scores of Brilliance/Scint/Fire are important for promotion and consumer selection Brands between MontBlanc and Louis Vuitton.

You use same scores to select car for you. but you use other motivation too. Its not contradictive . It is Help do best selection for you and spend minimum time ''

Sergey..., thats the problem!!!

LV cut = a Princess cut with concave entries..., I wouldnt suggest any scoring on this shape

MB cut = an independent cut designed by trial and error and could score well or could be adapted to score well if angles are changed a bit

Same with loads of other cuts patented?? or invented out there....

 

[diagem]

Serg..., how would you objectively grade the color for fancy colored Diamonds?

Any ideas for innovation in this arena???

I strongly believe the current system is flawed big time...., as long as consumers are educated they are purchasing "rare Yellow fancy colored Diamonds" and they are actually getting modified "capes" categorized as "Fancy Light Yellow" or even "Fancy Yellow"..., I think its a ticking time bomb that will explode in this industries face....


Any thoughts?

 

[diagem]

Any ideas on how Labs can start grading color on colorless Diamonds vs. face up position only?

Is it even possible?

How do we take factors like Fluo., black carbon inclusions, brutted girdles, naturals..., etc..., into consideration when grading face-up?

Or..., should these factors not be looked upon?

 

[Serg]

Diagem,

Re: Any ideas for innovation in this arena???

We are developing transparent color samples( to grade Tone ) + model human clustering grade

Did you read our article about color optimization ??

Re: Sergey..., thats the problem!!!

LV cut = a Princess cut with concave entries..., I wouldnt suggest any scoring on this shape

MB cut = an independent cut designed by trial and error and could score well or could be adapted to score well if angles are changed a bit

Correct optimization concavity cuts was not possible early my DC. Only newest version( what is not available yet) support correct visualization for concavity cuts
Such cuts will better a soon
Re: cut designed by trial and error
Are sure? By trial and error method only?

 

[diagem]

Date: 11/8/2008 1:16:41 PM
Author: Serg


Diagem,

Re: Any ideas for innovation in this arena???

We are developing transparent color samples( to grade Tone ) + model human clustering grade

Did you read our article about color optimization ??

No..., where can I find it?

Re: Sergey..., thats the problem!!!

LV cut = a Princess cut with concave entries..., I wouldnt suggest any scoring on this shape

MB cut = an independent cut designed by trial and error and could score well or could be adapted to score well if angles are changed a bit

Correct optimization concavity cuts was not possible early my DC. Only newest version( what is not available yet) support correct visualization for concavity cuts
Such cuts will better a soon

Re: cut designed by trial and error
Are sure? By trial and error method only?

Yes..., the beginnings were based on trial and error "only".

 

[Serg]

re:Yes..., the beginnings were based on trial and error "only".
when was it( beginnings) ?

 

[diagem]

Date: 11/8/2008 1:43:30 PM
Author: Serg
re:Yes..., the beginnings were based on trial and error ''only''.
when was it( beginnings) ?

long time ago....,

 

[Garry H (Cut Nut)]

Date: 11/8/2008 1:40:56 PM
Author: DiaGem

Date: 11/8/2008 1:16:41 PM
Author: Serg

Did you read our article about color optimization ??

No..., where can I find it?

Down the left side menu there are a few links to several pages DG
http://www.octonus.com/oct/projects/
I have pointed you to them before, but I suspect you have opened 1 - 2 pages only.

It might only be worthwhile discussing after you spend an hour reading - and then it might need a seperate thread?

 

[oldminer]

Although only one lab, ImaGem''s own operation in Surat, is using it yet, they have a GL3100 diamond grading device that does compute the color of D-J color diamonds with 1/3 grade repeatability and high conformance to GIA grading. The lab is supervised by a qualified GG who is allowed to make final color calls in case of rare situations such as large center black inclusions, but in 98%+ of the time, no such issue arises. From what I know, I believe color is measured face up and I assume it can be done on the entire range of color once sufficient diamonds of darker colors have been processed. To now, so little demand for GIA grading below J exists that compiling the data has not been an active pursuit. I believe color grading, with high conformance to the existing standards and traditions of the trade and GIA, is the least controversial path. I had suggested tone grading years ago to ImaGem and it was tested and abandoned. You will not get conformance to the GIA results using tone although the logic seemed strongly to suggest it. The physiology of our eyes does not match tone to color grade for all colors alike. The point of table up grading is certainly logical with diamonds since you can alter their perceived color with defined cutting tactics that existing cutting programs and trade knowledge give us. One wants to give diamond color grades based on how they look and not just the color of their rough material. Getting results from machines which give us expected GIA color grading results is the way to go. I know of no other material which is color graded the same way, but diamonds and precious gems are not color graded on sample swatches alone. There has always been a visual component and as diamonds get larger, they become darker although their GIA near colorless color grade does not diminish even as more light is absorbed due to size. In fancy colors, the rules change and the darker a diamond gets, the grade tends to strengthen, rather than diminish. It makes a challenging situation for technology.

Diamonds with transparency issues and large inclusions will always throw a monkey wrench into reliable digital grading, but a small number of exceptions is no reason to abandon overall improvement in grading reliability. GG''s can be used to fine tune the difficult 2% and in time technology will further reduce the "exceptions" This is exactly the case with all other technologies.

Another tool from ImaGem, already is far broader use, grades light return and can be used with any shape diamond and uses the same rules for the three important variables it measures. Marty Haske has pointed out to me that its single lighting model does not take into account as many choices as multi-light models, but the thorough research done by ImaGem and a highly important trade partner indicated one could rely on the results. It is simple and an elegant solution to the problem of directly assessed cut performance grading. The final grades are both numerical and categorized by common words, such as Excellent, etc. The numbers are a continuum and the words are the usual human simplifications that create gray, cross over zones. The numbers are repeatable within 2% for two of the measures and 4% for the third measure. This leaves very little to one''s imagination when making comparisons. EGL in North America and a large, growing chain of retailers are using this technology today as well as the ImaGem lab in Surat and my lab in the USA. I have had two large chain clients who used this technology with my lab in the past but unfortunately these chains are now bankrupt. Thankfully, it was not my fault and had nothing to do with measuring light performance.

I''ve been an unpaid adviser to ImaGem for 12 years. I suppose you might conclude a certain bias, but I am not pitching ImaGem. The industry needs to improve the consistency of grading and to add objective cut performance grading to diamonds. The technology wars must be waged by those people who have invested in the research. My participation has always been in hopes of seeing more consistent, more honest and more logic in the end results on lab reports. Whoever succeeds poses no threat to me.

 

[diagem]

Date: 11/9/2008 7:19:33 AM
Author: oldminer
Although only one lab, ImaGem''s own operation in Surat, is using it yet, they have a GL3100 diamond grading device that does compute the color of D-J color diamonds with 1/3 grade repeatability and high conformance to GIA grading. The lab is supervised by a qualified GG who is allowed to make final color calls in case of rare situations such as large center black inclusions, but in 98%+ of the time, no such issue arises. From what I know, I believe color is measured face up and I assume it can be done on the entire range of color once sufficient diamonds of darker colors have been processed. To now, so little demand for GIA grading below J exists that compiling the data has not been an active pursuit. I believe color grading, with high conformance to the existing standards and traditions of the trade and GIA, is the least controversial path. I had suggested tone grading years ago to ImaGem and it was tested and abandoned. You will not get conformance to the GIA results using tone although the logic seemed strongly to suggest it. The physiology of our eyes does not match tone to color grade for all colors alike. The point of table up grading is certainly logical with diamonds since you can alter their perceived color with defined cutting tactics that existing cutting programs and trade knowledge give us. One wants to give diamond color grades based on how they look and not just the color of their rough material. Getting results from machines which give us expected GIA color grading results is the way to go. I know of no other material which is color graded the same way, but diamonds and precious gems are not color graded on sample swatches alone. There has always been a visual component and as diamonds get larger, they become darker although their GIA near colorless color grade does not diminish even as more light is absorbed due to size. In fancy colors, the rules change and the darker a diamond gets, the grade tends to strengthen, rather than diminish. It makes a challenging situation for technology.

Thanks for your input Dave...,
Questions 1) On what logic would you expect Cutters to purchase the rough if not on the way the color looks in the rough stage?
2) Some manufacturers are cutting their products from polished goods altering the shapes to their needs..., how would they be able to calculate color based on a previous alteration or shape? For example..., I sometimes purchase regular stepcut shapes and re-cut them to other specific shapes to meet my clients needs.

3) You wrote: "...as diamonds become larger, they become darker...", do you mean a a 5 carat "H" will look like an "I" if compared to a 1 carat "H"?


Diamonds with transparency issues and large inclusions will always throw a monkey wrench into reliable digital grading, but a small number of exceptions is no reason to abandon overall improvement in grading reliability. GG''s can be used to fine tune the difficult 2% and in time technology will further reduce the ''exceptions'' This is exactly the case with all other technologies.

Another tool from ImaGem, already is far broader use, grades light return and can be used with any shape diamond and uses the same rules for the three important variables it measures. Marty Haske has pointed out to me that its single lighting model does not take into account as many choices as multi-light models, but the thorough research done by ImaGem and a highly important trade partner indicated one could rely on the results. It is simple and an elegant solution to the problem of directly assessed cut performance grading. The final grades are both numerical and categorized by common words, such as Excellent, etc. The numbers are a continuum and the words are the usual human simplifications that create gray, cross over zones. The numbers are repeatable within 2% for two of the measures and 4% for the third measure. This leaves very little to one''s imagination when making comparisons. EGL in North America and a large, growing chain of retailers are using this technology today as well as the ImaGem lab in Surat and my lab in the USA. I have had two large chain clients who used this technology with my lab in the past but unfortunately these chains are now bankrupt. Thankfully, it was not my fault and had nothing to do with measuring light performance.

But..., some of the newly cut shapes (branded/patented Diamonds) are not meant to be marketed as a high light performers? And even if tested..., the results would most probably be disappointing...

I''ve been an unpaid adviser to ImaGem for 12 years. I suppose you might conclude a certain bias, but I am not pitching ImaGem. The industry needs to improve the consistency of grading and to add objective cut performance grading to diamonds. The technology wars must be waged by those people who have invested in the research. My participation has always been in hopes of seeing more consistent, more honest and more logic in the end results on lab reports. Whoever succeeds poses no threat to me.

I agree with you that consistency of grading must improve..., but I dont see a way as there are way too many factors that (as far as I know) only humans can determine..., I realy dont see how colorless Diamonds can be graded based on face-up appearance in the polished state, just as I dont see how colored Diamonds can be objectively graded via face-up appearance only!

But I do understand the logic behind the thoughts...

 

[strmrdr]

The current color and clarity grades are a joke,,, way to subjective.
Color should be automated and done by machines calibrated to the same standard.
Different standards by different labs is downright criminal.

Any cut grade that does not take patterns and shape into account can not be trusted for fancies.

 

[diagem]

Date: 11/9/2008 10:04:15 AM
Author: strmrdr
The current color and clarity grades are a joke,,, way to subjective.
Color should be automated and done by machines calibrated to the same standard.
Different standards by different labs is downright criminal.

Any cut grade that does not take patterns and shape into account can not be trusted for fancies.

Karl..., doesn''t this saying should go with color grading and clarity too perhaps??

And I am willing to add "size" or "weight".

Any "color" grade that does not take "patterns" and "shape" [and size/weight] into account can not be trusted for ______.
Any "clarity" grade that does not take "patterns" and "shape" [and size/weight] into account can not be trusted for ______.


Debatable??

 

[strmrdr]

Date: 11/9/2008 10:30:06 AM
Author: DiaGem

Date: 11/9/2008 10:04:15 AM

Author: strmrdr

The current color and clarity grades are a joke,,, way to subjective.

Color should be automated and done by machines calibrated to the same standard.

Different standards by different labs is downright criminal.


Any cut grade that does not take patterns and shape into account can not be trusted for fancies.

Karl..., doesn't this saying should go with color grading and clarity too perhaps??


And I am willing to add 'size' or 'weight'.


Any 'color' grade that does not take 'patterns' and 'shape' [and size/weight] into account can not be trusted for ______.

Any 'clarity' grade that does not take 'patterns' and 'shape' [and size/weight] into account can not be trusted for ______.



Debatable??

I see where your coming from and my first thought is maybe.
It really depends on if your grading body color or face up color.
Clarity should I think be the same no matter the size and not scaled like today.
The eye visibility of inclusions does not change with diamond size so the grade should not either.

 

[diagem]

Date: 11/9/2008 10:53:19 AM
Author: strmrdr

Date: 11/9/2008 10:30:06 AM
Author: DiaGem

Date: 11/9/2008 10:04:15 AM

Author: strmrdr

The current color and clarity grades are a joke,,, way to subjective.

Color should be automated and done by machines calibrated to the same standard.

Different standards by different labs is downright criminal.


Any cut grade that does not take patterns and shape into account can not be trusted for fancies.

Karl..., doesn''t this saying should go with color grading and clarity too perhaps??


And I am willing to add ''size'' or ''weight''.


Any ''color'' grade that does not take ''patterns'' and ''shape'' [and size/weight] into account can not be trusted for ______.

Any ''clarity'' grade that does not take ''patterns'' and ''shape'' [and size/weight] into account can not be trusted for ______.



Debatable??

I see where your coming from and my first thought is maybe.
It really depends on if your grading body color or face up color.

Why? What would be the difference? If its not “automated”…, then why would there be a difference between face up and body?

Take for example an Asscher cut graded face-up as an “H” due to fluo. and right angle combinations, but body color wise it would have been graded a “J”…, would you consider that fair? Would you purchase this Diamond as an “H” (probably up to 2x or more than “J”)? Let say you purchase this Asscher as an “H”…, you set it in your dream ring…, and once you get home you look at the profile of the ring and notice the 20+% crown height (which is awesome for Asschers) is popping out of the setting and possesses a “Yellow tint” (after all…, “J” = yellowish tone)…, would you still think its fair?


Clarity should I think be the same no matter the size and not scaled like today.
The eye visibility of inclusions does not change with diamond size so the grade should not either.

Karl…, would it be fair to categorize the size of a feather graded as an SI1 in a 25 carat Diamond as an SI1 in a 1 carat Diamond?

Would it be fair to categorize a small black crystal inclusion which was graded as a VS1 in a 5 carat Princess cut (due to the masking of the brilliant faceting arrangements) and now will still be categorized as a VS1 in a EC of same or even smaller size in which is clearly eye-visible?

What about the position of the inclusion…, do you think it should be weighted when assigning a clarity grade?

 

[strmrdr]

te:[/b] 11/9/2008 1:09:45 PM
Author: DiaGem
Clarity should I think be the same no matter the size and not scaled like today.

The eye visibility of inclusions does not change with diamond size so the grade should not either.


Karl…, would it be fair to categorize the size of a feather graded as an SI1 in a 25 carat Diamond as an SI1 in a 1 carat Diamond?
YES!!!! they should be aprox the same size feather

Would it be fair to categorize a small black crystal inclusion which was graded as a VS1 in a 5 carat Princess cut (due to the masking of the brilliant faceting arrangements) and now will still be categorized as a VS1 in a EC of same or even smaller size in which is clearly eye-visible?
A vs1 inclusion by definition should only be visible under 10x if it is eye visible it isn't a VS1, masking should not be considered only inclusion size and type and it should be graded in darkfield only


What about the position of the inclusion…, do you think it should be weighted when assigning a clarity grade? No!!! only the visibility under 10x darkfield if one sticks to a ridicules system like today's.

[/quote]
Color I need to think about I'm not a fan of face up color grading.

 

[oldminer]

Questions 1) On what logic would you expect Cutters to purchase the rough if not on the way the color looks in the rough stage?
Cutters do use the color of the rough to judge what color range they will end up with, but actual color grading of only faceted diamonds is the GIA system. I don't want to do anything to change the system except to make it more highly repeatable. It is my belief that any system likely to be adopted must very, very closely match the expected outcome of GIA current grading. Change the whole logic of the system and no one will even look at it let alone want to adopt it. Such a move would really upset the market and trading of merchandise. The current system is not so technically proper, but it works very well for thousands of users. I want to bring technology forward which every current user will find comfortable and accurate.
2) Some manufacturers are cutting their products from polished goods altering the shapes to their needs..., how would they be able to calculate color based on a previous alteration or shape? For example..., I sometimes purchase regular stepcut shapes and re-cut them to other specific shapes to meet my clients needs.
Most times when you recut existing faceted, near colorless, diamonds the color grade won't be altered more than 1 grade, if at all. I suppose you could show me some extraordinary exception to this generalization, but exceptions do not dictate how business is conducted. That's the point of being an expert. Sergey has some great tools for predicting color from the rough or when recutting diamonds. It is something that can already be done with a high amount of confidence.


3) You wrote: "...as diamonds become larger, they become darker...", do you mean a a 5 carat "H" will look like an "I" if compared to a 1 carat "H"?
I sure do mean exactly what I said. A 5 carat GIA H color often looks like a 1 carat GIA I color. If you have 1 carat master color grading diamonds, you have to mentally make major color adjustments for larger diamonds. If you sawed off a 1 carat slab from the 5 carater you'd find the specimen was H color and not I. It was the extra thickness of the carats of material absorbing light and making it look darker. I bet you can't recut a GIA Fancy Yellow from a 1 carat GIA P/Q color , but that you might get a GIA Fancy Yelow from a 10 carat GIA P/Q diamond with proper recutting. It is the darkness of light absorption, and the unusual nature of GIA color grading, which makes this seemingly impossible event possible. Planning how to place the facets to deepen face-up fancy color concencentration works better on larger diamonds.

But..., some of the newly cut shapes (branded/patented's Diamonds) are not meant to be marketed as a high light performers? And even if tested..., the results would most probably be disappointing
That's okay with me. Grading is not free and one can choose to skip it. However, claiming a "brand" has great light performance while carefully avoiding proving the claim is hardly an honest way to misuse consumers. There are many lovely diamonds which cannot claim to be nearly as performance oriented as round diamonds. There are lots of consumers who want to have fair tools to compare any two or three diamonds to one another with objectivity. Giving the trade these tools will help make sales and inform buyers. I don't see this as anything but positive progress.

 

[diagem]

Date: 11/9/2008 1:37:56 PM
Author: strmrdr

Date: 11/9/2008 1:09:45 PM
Author: DiaGem
Clarity should I think be the same no matter the size and not scaled like today.

The eye visibility of inclusions does not change with diamond size so the grade should not either.


Karl…, would it be fair to categorize the size of a feather graded as an SI1 in a 25 carat Diamond as an SI1 in a 1 carat Diamond?
YES!!!! they should be aprox the same size feather

Are you serious with your answer??? My I ask you to rethink this specific answer?

Would it be fair to categorize a small black crystal inclusion which was graded as a VS1 in a 5 carat Princess cut (due to the masking of the brilliant faceting arrangements) and now will still be categorized as a VS1 in a EC of same or even smaller size in which is clearly eye-visible?
A vs1 inclusion by definition should only be visible under 10x if it is eye visible it isn''t a VS1, masking should not be considered only inclusion size and type and it should be graded in darkfield only
By who''s definition? GIA''s? Karl, I can assure you that a lot of black VS1''s are "clearly" visible with the naked eye..., so definition is one thing..., and reality is a second! (My opinion of course...)


What about the position of the inclusion…, do you think it should be weighted when assigning a clarity grade? No!!! only the visibility under 10x darkfield if one sticks to a ridicules system like today''s.

OK..., let me ask you it differently..., one black VS1 inclusion smack in the middle of the Diamond at girdle depth vs. the exact same inclusion positioned lower (closer to the culet area) resulting in multiple reflections through out the Diamond??? (both noticeable under 10x).

Color I need to think about I''m not a fan of face up color grading.

Let me know your thoughts once you base it....

 

[diagem]

Date: 11/9/2008 1:56:02 PM
Author: oldminer

Questions 1) On what logic would you expect Cutters to purchase the rough if not on the way the color looks in the rough stage?
Cutters do use the color of the rough to judge what color range they will end up with, but actual color grading of only faceted diamonds is the GIA system. I don''t want to do anything to change the system except to make it more highly repeatable. It is my belief that any system likely to be adopted must very, very closely match the expected outcome of GIA current grading. Change the whole logic of the system and no one will even look at it let alone want to adopt it. Such a move would really upset the market and trading of merchandise. The current system is not so technically proper, but it works very well for thousands of users. I want to bring technology forward which every current user will find comfortable and accurate.

Used to be that way..., but in the last few years..., the range was minimized to an accurate grade due to the fierce competition when rough purchasing.

2) Some manufacturers are cutting their products from polished goods altering the shapes to their needs..., how would they be able to calculate color based on a previous alteration or shape? For example..., I sometimes purchase regular stepcut shapes and re-cut them to other specific shapes to meet my clients needs.
Most times when you recut existing faceted, near colorless, diamonds the color grade won''t be altered more than 1 grade, if at all. I suppose you could show me some extraordinary exception to this generalization, but exceptions do not dictate how business is conducted. That''s the point of being an expert. Sergey has some great tools for predicting color from the rough or when recutting diamonds. It is something that can already be done with a high amount of confidence.

I would tend to agree with you on the near colorless Diamonds..., it gets a bit more complicated when taking lower colored Diamonds into this account..., not to mention fancy colored Diamonds...
I still have a problem trusting "tools" who predict the color that will come out of a specific rough material..., again, especially in the lower colors and fancy colors...



3) You wrote: ''...as diamonds become larger, they become darker...'', do you mean a a 5 carat ''H'' will look like an ''I'' if compared to a 1 carat ''H''?
I sure do mean exactly what I said. A 5 carat GIA H color often looks like a 1 carat GIA I color. If you have 1 carat master color grading diamonds, you have to mentally make major color adjustments for larger diamonds. If you sawed off a 1 carat slab from the 5 carater you''d find the specimen was H color and not I.

If you saw a slab of 1 carat of a 5 carater "I" color, you might easily find you have an E-F colored slab...

It was the extra thickness of the carats of material absorbing light and making it look darker. I bet you can''t recut a GIA Fancy Yellow from a 1 carat GIA P/Q color , but that you might get a GIA Fancy Yelow from a 10 carat GIA P/Q diamond with proper recutting. It is the darkness of light absorption, and the unusual nature of GIA color grading, which makes this seemingly impossible event possible. Planning how to place the facets to deepen face-up fancy color concencentration works better on larger diamonds.

I am not certain with your assertion above (but I need to think about it longer..., I will even make a tryout on this issue..., common sense tells me its all relative..., will let you know...

But..., some of the newly cut shapes (branded/patented''s Diamonds) are not meant to be marketed as a high light performers? And even if tested..., the results would most probably be disappointing
That''s okay with me. Grading is not free and one can choose to skip it. However, claiming a ''brand'' has great light performance while carefully avoiding proving the claim is hardly an honest way to misuse consumers. There are many lovely diamonds which cannot claim to be nearly as performance oriented as round diamonds. There are lots of consumers who want to have fair tools to compare any two or three diamonds to one another with objectivity. Giving the trade these tools will help make sales and inform buyers. I don''t see this as anything but positive progress.

Agreed 110%..., and we all know there are plenty of those claims around in the market

.

 

[strmrdr]

Date: 11/9/2008 4:59:38 PM
Author: DiaGem

Date: 11/9/2008 1:37:56 PM

Author: strmrdr

Date: 11/9/2008 1:09:45 PM

Author: DiaGem

Clarity should I think be the same no matter the size and not scaled like today.


The eye visibility of inclusions does not change with diamond size so the grade should not either.



Karl…, would it be fair to categorize the size of a feather graded as an SI1 in a 25 carat Diamond as an SI1 in a 1 carat Diamond?

YES!!!! they should be aprox the same size feather



Are you serious with your answer??? My I ask you to rethink this specific answer?

Absolutely serious!!!!! The size of the diamond should have nothing to do with inclusion size for any given grade.
A class action lawsuit over this would be interesting and the industry would lose.
If GIA actually graded diamonds the way they say the do then I am 100% right!!!!
per GIA:


What is the GIA Clarity Scale for diamonds?


Answer:

Diamonds have internal features, called inclusions, and surface irregularities, called blemishes. Together, they're called clarity characteristics. A clarity grade is determined by the relative absence of clarity characteristics.

Flawless (FL): no blemishes or inclusions when examined by a skilled grader under 10X magnification.

Internally Flawless (IF): no inclusions when examined by a skilled grader, and only insignificant blemishes under 10X.

Very Very Slightly Included (VVS1 and VVS2): contain minute inclusions that are difficult for even a skilled grader to locate under 10X. VVS1: extremely difficult to see, visible only from the pavilion or small and shallow enough to be removed by minor repolishing. VVS2: very difficult to see.

Very Slightly Included (VS1 and VS2): contain minor inclusions ranging from difficult (VS1) to somewhat easy (VS2) for a trained grader to see under 10X.

Slightly Included (SI1 and SI2): contain noticeable inclusions which are easy (SI1) or very easy (SI2) to see under 10X. In some SIs, inclusions can be seen with the unaided eye.

Included (I1, I2, I3): contain inclusions which are obvious to a trained grader under 10X, can often be easily seen face-up with the unaided eye, seriously affect the stone's potential durability, or are so numerous they affect transparency and brilliance.


http://www.gia.edu/library/4286/6278/faq_detail_page.cfm

 

[Garry H (Cut Nut)]

Date: 11/9/2008 9:41:35 AM
Author: DiaGem

Date: 11/9/2008 7:19:33 AM
Author: oldminer
Although only one lab, ImaGem''s own operation in Surat, is using it yet, they have a GL3100 diamond grading device that does compute the color of D-J color diamonds with 1/3 grade repeatability and high conformance to GIA grading. The lab is supervised by a qualified GG who is allowed to make final color calls in case of rare situations such as large center black inclusions, but in 98%+ of the time, no such issue arises. From what I know, I believe color is measured face up and I assume it can be done on the entire range of color once sufficient diamonds of darker colors have been processed. To now, so little demand for GIA grading below J exists that compiling the data has not been an active pursuit. I believe color grading, with high conformance to the existing standards and traditions of the trade and GIA, is the least controversial path. I had suggested tone grading years ago to ImaGem and it was tested and abandoned. You will not get conformance to the GIA results using tone although the logic seemed strongly to suggest it. The physiology of our eyes does not match tone to color grade for all colors alike. The point of table up grading is certainly logical with diamonds since you can alter their perceived color with defined cutting tactics that existing cutting programs and trade knowledge give us. One wants to give diamond color grades based on how they look and not just the color of their rough material. Getting results from machines which give us expected GIA color grading results is the way to go. I know of no other material which is color graded the same way, but diamonds and precious gems are not color graded on sample swatches alone. There has always been a visual component and as diamonds get larger, they become darker although their GIA near colorless color grade does not diminish even as more light is absorbed due to size. In fancy colors, the rules change and the darker a diamond gets, the grade tends to strengthen, rather than diminish. It makes a challenging situation for technology.

Thanks for your input Dave...,
Questions 1) On what logic would you expect Cutters to purchase the rough if not on the way the color looks in the rough stage?
2) Some manufacturers are cutting their products from polished goods altering the shapes to their needs..., how would they be able to calculate color based on a previous alteration or shape? For example..., I sometimes purchase regular stepcut shapes and re-cut them to other specific shapes to meet my clients needs.

3) You wrote: ''...as diamonds become larger, they become darker...'', do you mean a a 5 carat ''H'' will look like an ''I'' if compared to a 1 carat ''H''?

Dear DG - the image below shows that indeed the colour of the rough when polished changes when viewed thru the sides of the polished.
These are the same spectrum rough. Identical!

You do this you must know that recutting an emerald cut into a radiant will result in a lower face up colour and can sometimes effect the side view too.
This is a consumer protection website and if we are serious then we need to re-engineer back from consumer demands - not continue the "at our convenience requirements". The science can achieve it, as per Imagem and the various others who are playing in that arena.

Also the difference in percieved colour of a .50ct H to a 10ct H is huge DG - surely you noticed?
You think it helps us sell big diamonds?
KISS

 

[Serg]

Date: 11/9/2008 6:31:20 PM
Author: strmrdr

Date: 11/9/2008 4:59:38 PM
Author: DiaGem

Date: 11/9/2008 1:37:56 PM

Author: strmrdr

Date: 11/9/2008 1:09:45 PM

Author: DiaGem

Clarity should I think be the same no matter the size and not scaled like today.


The eye visibility of inclusions does not change with diamond size so the grade should not either.



Karl…, would it be fair to categorize the size of a feather graded as an SI1 in a 25 carat Diamond as an SI1 in a 1 carat Diamond?

YES!!!! they should be aprox the same size feather



Are you serious with your answer??? My I ask you to rethink this specific answer?

Absolutely serious!!!!! The size of the diamond should have nothing to do with inclusion size for any given grade.
A class action lawsuit over this would be interesting and the industry would lose.
If GIA actually graded diamonds the way they say the do then I am 100% right!!!!
per GIA:


What is the GIA Clarity Scale for diamonds?


Answer:

Diamonds have internal features, called inclusions, and surface irregularities, called blemishes. Together, they''re called clarity characteristics. A clarity grade is determined by the relative absence of clarity characteristics.

Flawless (FL): no blemishes or inclusions when examined by a skilled grader under 10X magnification.

Internally Flawless (IF): no inclusions when examined by a skilled grader, and only insignificant blemishes under 10X.

Very Very Slightly Included (VVS1 and VVS2): contain minute inclusions that are difficult for even a skilled grader to locate under 10X. VVS1: extremely difficult to see, visible only from the pavilion or small and shallow enough to be removed by minor repolishing. VVS2: very difficult to see.

Very Slightly Included (VS1 and VS2): contain minor inclusions ranging from difficult (VS1) to somewhat easy (VS2) for a trained grader to see under 10X.

Slightly Included (SI1 and SI2): contain noticeable inclusions which are easy (SI1) or very easy (SI2) to see under 10X. In some SIs, inclusions can be seen with the unaided eye.

Included (I1, I2, I3): contain inclusions which are obvious to a trained grader under 10X, can often be easily seen face-up with the unaided eye, seriously affect the stone''s potential durability, or are so numerous they affect transparency and brilliance.


http://www.gia.edu/library/4286/6278/faq_detail_page.cfm

re:If GIA actually graded diamonds the way they say the do then I am 100% right!!!!


For my observation there are difference between GIA training courses and GIA laboratory methodic. I suppose( i can not proof, but I saw examples) what clarity grade for 3+(5+)Ct are diffirent from
0.5 ct clarity grade
I see fundamental physical reason why Physical size VVS1 inclusion could be bigger 5+ct diamond than VVS1 in 0.5 ct
But big inclusions like SI1 should have same size for all diamonds9 Unfortunately current practice is diffident) Some reason of problems come from I1-I3 definitions
See
small inclusions defined in absolute coordinates ( for example 5-20 microns for VVS1)
But I2-I3 defined like % from diamond surface

In such case size for I inclusions depends from diamond size. SI inclusion size should correlate with I1-I3 sizes(Otherwise you will receive big step between SI and I1 for big diamonds)

Problems come from contradictive definitions between VVS-S1 inclusions and Pike type inclusions

You can think what GIA uses one more rule : "Relative difference between any two types inclusions should be similar for all diamond sizes"

 

[strmrdr]

Date: 11/10/2008 6:56:23 AM
Author: Serg


You can think what GIA uses one more rule : 'Relative difference between any two types inclusions should be similar for all diamond sizes'

That is my understanding also that they have hidden criteria..
But it is not correct based on their published criteria and not publicly saying so is flat out fraud.
An EC with an eye visible inclusion is a si at best at any size anything else is fraud and all the labs that grades track gia grading are guilty of it also.
It is another of those evil practices the trade as a whole has built up over the years.

 

[diagem]

Date: 11/9/2008 7:08:44 PM
Author: Garry H (Cut Nut)

Date: 11/9/2008 9:41:35 AM
Author: DiaGem

Date: 11/9/2008 7:19:33 AM
Author: oldminer
Although only one lab, ImaGem''s own operation in Surat, is using it yet, they have a GL3100 diamond grading device that does compute the color of D-J color diamonds with 1/3 grade repeatability and high conformance to GIA grading. The lab is supervised by a qualified GG who is allowed to make final color calls in case of rare situations such as large center black inclusions, but in 98%+ of the time, no such issue arises. From what I know, I believe color is measured face up and I assume it can be done on the entire range of color once sufficient diamonds of darker colors have been processed. To now, so little demand for GIA grading below J exists that compiling the data has not been an active pursuit. I believe color grading, with high conformance to the existing standards and traditions of the trade and GIA, is the least controversial path. I had suggested tone grading years ago to ImaGem and it was tested and abandoned. You will not get conformance to the GIA results using tone although the logic seemed strongly to suggest it. The physiology of our eyes does not match tone to color grade for all colors alike. The point of table up grading is certainly logical with diamonds since you can alter their perceived color with defined cutting tactics that existing cutting programs and trade knowledge give us. One wants to give diamond color grades based on how they look and not just the color of their rough material. Getting results from machines which give us expected GIA color grading results is the way to go. I know of no other material which is color graded the same way, but diamonds and precious gems are not color graded on sample swatches alone. There has always been a visual component and as diamonds get larger, they become darker although their GIA near colorless color grade does not diminish even as more light is absorbed due to size. In fancy colors, the rules change and the darker a diamond gets, the grade tends to strengthen, rather than diminish. It makes a challenging situation for technology.

Thanks for your input Dave...,
Questions 1) On what logic would you expect Cutters to purchase the rough if not on the way the color looks in the rough stage?
2) Some manufacturers are cutting their products from polished goods altering the shapes to their needs..., how would they be able to calculate color based on a previous alteration or shape? For example..., I sometimes purchase regular stepcut shapes and re-cut them to other specific shapes to meet my clients needs.

3) You wrote: ''...as diamonds become larger, they become darker...'', do you mean a a 5 carat ''H'' will look like an ''I'' if compared to a 1 carat ''H''?

Dear DG - the image below shows that indeed the colour of the rough when polished changes when viewed thru the sides of the polished.
These are the same spectrum rough. Identical!

Naturally it changes some of the times depending on the position, shape and faceting arrangement (of the polished)…, one thing is for sure…, there is no straight rule about the change…, it can go both ways, darker and lighter. My opinion is based on my personal experience and not aimed at a specific "spectrum".

You do this you must know that recutting an emerald cut into a radiant will result in a lower face up colour and can sometimes effect the side view too.

Yes…, but Dave is right that the change would probably be minimal (if any) in the colorless range (G+) and as I said…, it becomes more significant as the tint in the Diamond material deepens (H-I and lower).

This is a consumer protection website and if we are serious then we need to re-engineer back from consumer demands - not continue the ''at our convenience requirements''. The science can achieve it, as per Imagem and the various others who are playing in that arena.

Agree with you (about PS being a consumer protection oriented website)…, but show me a serious way to reverse engineer the color grading system by grading colorless Diamonds via face-up appearance only…, I have yet seen an example on this issue let alone the “science” you and Dave mention…., and please explain or show me the connection between face-up color grading and consumer demand/request and how it protects “only” and not abuse “a little” the consumers…, I somewhat believe there are always two sides to the coin… (in some instances it might protect and maybe not).

How do you see the face-up color-Grading (which is GIA’s system for grading today) in the "fancy" colored Diamond arena is protecting the consumers? I think it does the opposite (mainly in the lighter hue’s)…, and I am not sure it will not do the opposite in the colorless ranges as well.
A lot of you experts (not pointing to anyone specific) out there measure the qualities of Diamonds based on face up appearance mainly…, I keep saying its not JUST about face-up…, I think a Diamonds qualities MUST be visually measured in a three dimensional form… , and marketing fancy colored Diamonds as "rarer" color grades than they actually are (in all other viewing positions) is not fair towards the consumers, or at least as per my opinion….

Also the difference in percieved colour of a .50ct H to a 10ct H is huge DG - surely you noticed?
You think it helps us sell big diamonds?

Sorry..., dont agree with you on this point. I believe you are exaggerating here...

KISS

 

[oldminer]

In every other color grading system or product in the entire world, I only think the way they grade "color" by what is seen with the eye, even if it is measured and quantified digitally. ONLY in diamonds, does the "color grading system" currently in common use, adjust the "color" reported to about the size of a 0.50ct diamond sample. DiaGem has told me in his reply that a 10 carat GIA H might have the color of an E/F color 0.50ct stone if a sample were to be removed. There is no other such confusing or illogical system in use for any other color grading that I know of.
Diamonds are very unique and highly valuable. We can''t forget this. Possibly diamonds have to be color graded differently than wallpaper, paint or cloth. Huge economic upset would come with a real revision of color grading diamonds where less valuable commodities would not suffer if terminology were to be altered.

Now, I have always promoted advancing color grading without rocking the boat of current practice, but this lack of scientific approach is one of the main difficulties for many of us who struggle with advancing the technology and also one of the main reasons experts rarely can agree on exact color grades with the current system. I''d be interested and open to suggestions as to how to make diamond color grading more logical WITHOUT killing the business and further eroding profits. Think of the consequences of change before asking an entire industry to make itself over. There are many a catch 22 involved here. Idealistic philosophy aside, what are the practical solutions which have any chance of being accepted? We can all aspire to a perfect world, but suggestions in a vacuum with no reality attached, are a wasted effort.

 

[diagem]

Date: 11/10/2008 8:48:20 AM
Author: oldminer
In every other color grading system or product in the entire world, I only think the way they grade ''color'' by what is seen with the eye, even if it is measured and quantified digitally. ONLY in diamonds, does the ''color grading system'' currently in common use, adjust the ''color'' reported to about the size of a 0.50ct diamond sample. DiaGem has told me in his reply that a 10 carat GIA H might have the color of an E/F color 0.50ct stone if a sample were to be removed. There is no other such confusing or illogical system in use for any other color grading that I know of.
Diamonds are very unique and highly valuable. We can''t forget this. Possibly diamonds have to be color graded differently than wallpaper, paint or cloth. Huge economic upset would come with a real revision of color grading diamonds where less valuable commodities would not suffer if terminology were to be altered.

Now, I have always promoted advancing color grading without rocking the boat of current practice, but this lack of scientific approach is one of the main difficulties for many of us who struggle with advancing the technology and also one of the main reasons experts rarely can agree on exact color grades with the current system. I''d be interested and open to suggestions as to how to make diamond color grading more logical WITHOUT killing the business and further eroding profits. Think of the consequences of change before asking an entire industry to make itself over. There are many a catch 22 involved here. Idealistic philosophy aside, what are the practical solutions which have any chance of being accepted? We can all aspire to a perfect world, but suggestions in a vacuum with no reality attached, are a wasted effort.

Dave..., I guess you are confused...especially when it comes to translating my writing..., sorry, maybe I should have worded it better...

But I wrote:

"If you saw a slab of 1 carat of a 5 carater "I" color, you might easily find you have an E-F colored slab..."

I meant to say that if you take a 5 carat "I" colored Diamond and saw (cut a piece off) a one carat slab (a word you used) off (the 5 carat whole)..., you can find that the 1 carat slab is actually a E-F colored slab! The 4 remaining whole carats will most probably stay an "I" color!

But as I said elsewhere in this thread...., true its confusing but still its not as simple as you think or write it is..., you can easily find yourself taking a five carat "I" colored Diamond and cut a 1 carat slab off (again) and the result will be that the 1 carat slab is tinted brown and the remaining four carat whole actually turned "D" color!

Dave too many factors that can change the nature of Diamonds appearances! Its not easy as ABC, let alone comparing it to "paint, wallpaper or even cloth"...

 

[diagem]

Date: 11/10/2008 6:56:23 AM
Author: Serg

re:If GIA actually graded diamonds the way they say the do then I am 100% right!!!!


For my observation there are difference between GIA training courses and GIA laboratory methodic. I suppose( i can not proof, but I saw examples) what clarity grade for 3+(5+)Ct are diffirent from
0.5 ct clarity grade

I see fundamental physical reason why Physical size VVS1 inclusion could be bigger 5+ct diamond than VVS1 in 0.5 ct
But big inclusions like SI1 should have same size for all diamonds9 Unfortunately current practice is diffident) Some reason of problems come from I1-I3 definitionsExactly...., good explanation Serg...., so as long as I1-3 clarity grade are not defined the same as SI clarity is..., the size of the SI inclusion should be calculated vs. the size of the Diamond in subject (or based on the % it covers on the Diamond surface.)


See
small inclusions defined in absolute coordinates ( for example 5-20 microns for VVS1)
But I2-I3 defined like % from diamond surface

In such case size for I inclusions depends from diamond size. SI inclusion size should correlate with I1-I3 sizes(Otherwise you will receive big step between SI and I1 for big diamonds)

Problems come from contradictive definitions between VVS-S1 inclusions and Pike type inclusions

You can think what GIA uses one more rule : ''Relative difference between any two types inclusions should be similar for all diamond sizes''

 

[diagem]

Date: 11/10/2008 7:32:45 AM
Author: strmrdr

Date: 11/10/2008 6:56:23 AM
Author: Serg


You can think what GIA uses one more rule : ''Relative difference between any two types inclusions should be similar for all diamond sizes''

That is my understanding also that they have hidden criteria..
But it is not correct based on their published criteria and not publicly saying so is flat out fraud.
An EC with an eye visible inclusion is a si at best at any size anything else is fraud and all the labs that grades track gia grading are guilty of it also.
It is another of those evil practices the trade as a whole has built up over the years.

Karl..., when does that eye visible SI become an I1 or 2 or 3???

 

[strmrdr]

Date: 11/10/2008 9:38:01 AM
Author: DiaGem

Date: 11/10/2008 7:32:45 AM

Author: strmrdr

Date: 11/10/2008 6:56:23 AM

Author: Serg



You can think what GIA uses one more rule : ''Relative difference between any two types inclusions should be similar for all diamond sizes''

That is my understanding also that they have hidden criteria..

But it is not correct based on their published criteria and not publicly saying so is flat out fraud.

An EC with an eye visible inclusion is a si at best at any size anything else is fraud and all the labs that grades track gia grading are guilty of it also.

It is another of those evil practices the trade as a whole has built up over the years.

Karl..., when does that eye visible SI become an I1 or 2 or 3???

gia quote:

Slightly Included (SI1 and SI2): contain noticeable inclusions which are easy (SI1) or very easy (SI2) to see under 10X. In some SIs, inclusions can be seen with the unaided eye.

Included (I1, I2, I3): contain inclusions which are obvious to a trained grader under 10X, can often be easily seen face-up with the unaided eye, seriously affect the stone''s potential durability, or are so numerous they affect transparency and brilliance.