Changing the hue of a Fancy Colored Diamond by re-cutting, the continuation....

[diagem]

I fully agree with Marty Haske and believe the other thread (IDEX Closes News Forum JKD/GIA Stafford Casehttps://www.pricescope.com/community/threads/idex-closes-news-forum-jkd-gia-stafford-case.88950/) should be left to concentrate on the MAIN subject of that specific thread...


So I hope we can continue the issue of what cutting can potentially do for Fancy Colored Diamonds???

Many times while cutting a fancy colored Diamond from rough..., I clearly notice that the color concentration is dependent on the natural skin (and the depth of the skin) of the rough...

The higher the yield..., the more intense the color...., the deeper you cut in the natural rough..., the lighter the color becomes...

Serge..., can your technology identify these types of material? If yes, can it be identified prior to the windowing (or only after)?

 

[Serg]

Date: 7/4/2008 8:12:44 AM
Author:DiaGem
I fully agree with Marty Haske and believe the other thread (IDEX Closes News Forum JKD/GIA Stafford Casehttps://www.pricescope.com/community/threads/idex-closes-news-forum-jkd-gia-stafford-case.88950/) should be left to concentrate on the MAIN subject of that specific thread...


So I hope we can continue the issue of what cutting can potentially do for Fancy Colored Diamonds???

Many times while cutting a fancy colored Diamond from rough..., I clearly notice that the color concentration is dependent on the natural skin (and the depth of the skin) of the rough...

The higher the yield..., the more intense the color...., the deeper you cut in the natural rough..., the lighter the color becomes...

Serge..., can your technology identify these types of material? If yes, can it be identified prior to the windowing (or only after)?

Diagem,

I need remove skin in any case. Skin should not come to polish diamond.
radial color zoning you can control( measure) due semipolish process.
simply :
1)firstly you need check absorption spectrum on small windows
2) Than after you remove more material
If absorption spectrums( per length) are different you have rough with radial zoning

 

[diagem]

Date: 7/4/2008 8:29:37 AM
Author: Serg

Date: 7/4/2008 8:12:44 AM
Author:DiaGem
I fully agree with Marty Haske and believe the other thread (IDEX Closes News Forum JKD/GIA Stafford Casehttps://www.pricescope.com/community/threads/idex-closes-news-forum-jkd-gia-stafford-case.88950/) should be left to concentrate on the MAIN subject of that specific thread...


So I hope we can continue the issue of what cutting can potentially do for Fancy Colored Diamonds???

Many times while cutting a fancy colored Diamond from rough..., I clearly notice that the color concentration is dependent on the natural skin (and the depth of the skin) of the rough...

The higher the yield..., the more intense the color...., the deeper you cut in the natural rough..., the lighter the color becomes...

Serge..., can your technology identify these types of material? If yes, can it be identified prior to the windowing (or only after)?

Diagem,

I need remove skin in any case. Skin should not come to polish diamond.
radial color zoning you can control( measure) due semipolish process.
simply :
1)firstly you need check absorption spectrum on small windows
2) Than after you remove more material

If absorption spectrums( per length) are different you have rough with radial zoning

So my understanding is you need to polish prior to checking..., correct?
There is no way to measure depth of radial zoning with out windowing first?

 

[diagem]

Serg..., what about colored material based on a type of "internal graining"..., typically on browns and some pinks?
I mean the types that consist of the brown marks that show up as straight colored lines when louped?

For example..., when cutting the Diamond on the X, the the lines are noticeable in the face-up position, and while cutting the Diamond on the Y the lines disappear from the face up and in turn the show the color in the face-up position... (I hope I am explaining myself ok...

)

 

[Serg]

Date: 7/4/2008 9:33:44 AM
Author: DiaGem

Date: 7/4/2008 8:29:37 AM
Author: Serg

Date: 7/4/2008 8:12:44 AM
Author:DiaGem
I fully agree with Marty Haske and believe the other thread (IDEX Closes News Forum JKD/GIA Stafford Casehttps://www.pricescope.com/community/threads/idex-closes-news-forum-jkd-gia-stafford-case.88950/) should be left to concentrate on the MAIN subject of that specific thread...


So I hope we can continue the issue of what cutting can potentially do for Fancy Colored Diamonds???

Many times while cutting a fancy colored Diamond from rough..., I clearly notice that the color concentration is dependent on the natural skin (and the depth of the skin) of the rough...

The higher the yield..., the more intense the color...., the deeper you cut in the natural rough..., the lighter the color becomes...

Serge..., can your technology identify these types of material? If yes, can it be identified prior to the windowing (or only after)?

Diagem,

I need remove skin in any case. Skin should not come to polish diamond.
radial color zoning you can control( measure) due semipolish process.
simply :
1)firstly you need check absorption spectrum on small windows
2) Than after you remove more material


If absorption spectrums( per length) are different you have rough with radial zoning

So my understanding is you need to polish prior to checking..., correct?
There is no way to measure depth of radial zoning with out windowing first?

without windowing you can not receive absorption spectrum

other way to measure for different directions(lenghts)

 

[Serg]

Date: 7/4/2008 10:18:07 AM
Author: DiaGem
Serg..., what about colored material based on a type of ''internal graining''..., typically on browns and some pinks?
I mean the types that consist of the brown marks that show up as straight colored lines when louped?

For example..., when cutting the Diamond on the X, the the lines are noticeable in the face-up position, and while cutting the Diamond on the Y the lines disappear from the face up and in turn the show the color in the face-up position... (I hope I am explaining myself ok...

)

Diagem,
I do not know. Mow I am working with yellow mostly .
Most probably better use inclusion model because graining has local influence to color

 

[diagem]

Date: 7/4/2008 1:01:31 PM
Author: Serg

Date: 7/4/2008 10:18:07 AM
Author: DiaGem
Serg..., what about colored material based on a type of ''internal graining''..., typically on browns and some pinks?
I mean the types that consist of the brown marks that show up as straight colored lines when louped?

For example..., when cutting the Diamond on the X, the the lines are noticeable in the face-up position, and while cutting the Diamond on the Y the lines disappear from the face up and in turn the show the color in the face-up position... (I hope I am explaining myself ok...

)

Diagem,
I do not know. Mow I am working with yellow mostly .
Most probably better use inclusion model because graining has local influence to color

Serg..., I think there is a HUGE difference in the fashion Lab''s grade Yellow vs. the rest..... (because of the quantities of yellows out there vs. the rare colors.)

The intensity of a fancy light yellow would equal a fancy (or higher) grade in pink or blue or other colors..., how do you differentiate between the color potential and their grading systems in your technology?

There are so many factors that can change the colors during the cutting process..., is it even possible to take them into consideration while developing these technological tools?

It just seems to me you are able to scratch the tip of the iceberg when you are talking fancy colored Diamonds...

 

[Serg]

Date: 7/4/2008 4:05:22 PM
Author: DiaGem

Date: 7/4/2008 1:01:31 PM
Author: Serg

Date: 7/4/2008 10:18:07 AM
Author: DiaGem
Serg..., what about colored material based on a type of ''internal graining''..., typically on browns and some pinks?
I mean the types that consist of the brown marks that show up as straight colored lines when louped?

For example..., when cutting the Diamond on the X, the the lines are noticeable in the face-up position, and while cutting the Diamond on the Y the lines disappear from the face up and in turn the show the color in the face-up position... (I hope I am explaining myself ok...

)

Diagem,
I do not know. Mow I am working with yellow mostly .
Most probably better use inclusion model because graining has local influence to color

Serg..., I think there is a HUGE difference in the fashion Lab''s grade Yellow vs. the rest..... (because of the quantities of yellows out there vs. the rare colors.)

The intensity of a fancy light yellow would equal a fancy (or higher) grade in pink or blue or other colors..., how do you differentiate between the color potential and their grading systems in your technology?

There are so many factors that can change the colors during the cutting process..., is it even possible to take them into consideration while developing these technological tools?

It just seems to me you are able to scratch the tip of the iceberg when you are talking fancy colored Diamonds...

re:how do you differentiate between the color potential and their grading systems in your technology?

We do grade for each interesting combination cut proportions, see example

re:There are so many factors that can change the colors during the cutting process...,

Cut and spectrum are most important factors

 

[Serg]

Same stone in Munsell system

 

[diagem]

Date: 7/4/2008 4:34:51 PM
Author: Serg

Date: 7/4/2008 4:05:22 PM
Author: DiaGem

Date: 7/4/2008 1:01:31 PM
Author: Serg

Date: 7/4/2008 10:18:07 AM
Author: DiaGem
Serg..., what about colored material based on a type of ''internal graining''..., typically on browns and some pinks?
I mean the types that consist of the brown marks that show up as straight colored lines when louped?

For example..., when cutting the Diamond on the X, the the lines are noticeable in the face-up position, and while cutting the Diamond on the Y the lines disappear from the face up and in turn the show the color in the face-up position... (I hope I am explaining myself ok...

)

Diagem,
I do not know. Mow I am working with yellow mostly .
Most probably better use inclusion model because graining has local influence to color

Serg..., I think there is a HUGE difference in the fashion Lab''s grade Yellow vs. the rest..... (because of the quantities of yellows out there vs. the rare colors.)

The intensity of a fancy light yellow would equal a fancy (or higher) grade in pink or blue or other colors..., how do you differentiate between the color potential and their grading systems in your technology?

There are so many factors that can change the colors during the cutting process..., is it even possible to take them into consideration while developing these technological tools?

It just seems to me you are able to scratch the tip of the iceberg when you are talking fancy colored Diamonds...

re:how do you differentiate between the color potential and their grading systems in your technology?

We do grade for each interesting combination cut proportions, see example

re:There are so many factors that can change the colors during the cutting process...,

Cut and spectrum are most important factors

Serg..., I am sorry I am not a tech wiz..., please explain what I am looking at...

 

[Serg]

Diagem,

Do you know what is Munsell system? Labs us Munsell book to grade fancy color diamonds( compare diamond with piece of paper).
We build histogram of color in Munsell( blue cycles) , Luv( red cycles) systems
You can easy see how big Part Vivid, Intense, Fancy in cut depends from proportions .
Depends from Histogram we give final grade.
Task is find to proportions with best final theoretical grade.
Boundaries between color zones ( Vivid, Intense, ..) we took from Munsell , because Labs use Munsell. We slightly change boundaries in Luv color space. ( we used properties Luv color space to fix problem in boundaries what came from Munsell color system )
Of course our boundaries could be different from Labs boundaries ( Labs did not publish any standards here)
But such difference is not critical to task improve color by proportions.

 

[diagem]

Date: 7/5/2008 1:18:53 PM
Author: Serg

Diagem,

Do you know what is Munsell system? Labs us Munsell book to grade fancy color diamonds( compare diamond with piece of paper).
We build histogram of color in Munsell( blue cycles) , Luv( red cycles) systems
You can easy see how big Part Vivid, Intense, Fancy in cut depends from proportions .
Depends from Histogram we give final grade.
Task is find to proportions with best final theoretical grade.
Boundaries between color zones ( Vivid, Intense, ..) we took from Munsell , because Labs use Munsell. We slightly change boundaries in Luv color space. ( we used properties Luv color space to fix problem in boundaries what came from Munsell color system )
Of course our boundaries could be different from Labs boundaries ( Labs did not publish any standards here)
But such difference is not critical to task improve color by proportions.

I still think there is more to it..., the boundaries are key..., there is too much value on the line..., and missing the thin line between the boundaries can mean "break or make"...

You say you work mainly with yellows (I hope more is coming...), but as I said above..., when seeking the boundaries positions between the grades (light fancy, fancy, fancy intense and vivid)..., I noticed that there is a huge difference between the color intensity of a graded intense yellow vs. a intense pink or blue....

Perhaps an issue of rarity??

 

[Serg]

re:I noticed that there is a huge difference between the color intensity of a graded intense yellow vs. a intense pink or blue....


Labs prefer relative ( reference) grading systems. there is easy create relative grading system, you need only samples and human grade.
but problems come later. there are quiet different Vivid pink diamonds .

similar problem with ASG cut grade system. Emerald can receive ASG0 cut grade, Again problem come from relative grade.

right way is create reasonable boundaries for yellow fancy color in any uniform color system( Like Luv) , verify its on real diamonds and then use SAME boundaries for other Hue( Tone) like pink, red, blue

 

[Garry H (Cut Nut)]

Date: 7/5/2008 4:04:40 PM
Author: Serg

re:I noticed that there is a huge difference between the color intensity of a graded intense yellow vs. a intense pink or blue....


Labs prefer relative ( reference) grading systems. there is easy create relative grading system, you need only samples and human grade.
but problems come later. there are quiet different Vivid pink diamonds .

similar problem with ASG cut grade system. Emerald can receive ASG0 cut grade, Again problem come from relative grade.

right way is create reasonable boundaries for yellow fancy color in any uniform color system( Like Luv) , verify its on real diamonds and then use SAME boundaries for other Hue( Tone) like pink, red, blue

I will try to explain what i think each of you is saying / asking the other.

1. regional colour - the best example would be green where radiation staining is only on the outer skin. Sergey''s DiamCalc and spectrum approach will be less useful. But with arglye pink with strong colour banding / graining, combining Sergey''s software and an expert planner / polisher, there will not be problems.


2. Labs give Vivid to only very saturated yellows, but a pink, blue or green that might be the equivalent of yellow Fancy Intense in a truly objective grade system would be given Vivid because of its much greater rarity. It is a human judgement / commercial decision - I think it is reasonable, but of course a grading system that was more truly open ended would be advantageous - just as it should be for cut grades for colourless diamonds.

hope that helps

 

[Serg]

Date: 7/6/2008 12:09:02 AM
Author: Garry H (Cut Nut)

Date: 7/5/2008 4:04:40 PM
Author: Serg


re:I noticed that there is a huge difference between the color intensity of a graded intense yellow vs. a intense pink or blue....


Labs prefer relative ( reference) grading systems. there is easy create relative grading system, you need only samples and human grade.
but problems come later. there are quiet different Vivid pink diamonds .

similar problem with ASG cut grade system. Emerald can receive ASG0 cut grade, Again problem come from relative grade.

right way is create reasonable boundaries for yellow fancy color in any uniform color system( Like Luv) , verify its on real diamonds and then use SAME boundaries for other Hue( Tone) like pink, red, blue

I will try to explain what i think each of you is saying / asking the other.

1. regional colour - the best example would be green where radiation staining is only on the outer skin. Sergey''s DiamCalc and spectrum approach will be less useful. But with arglye pink with strong colour banding / graining, combining Sergey''s software and an expert planner / polisher, there will not be problems.


2. Labs give Vivid to only very saturated yellows, but a pink, blue or green that might be the equivalent of yellow Fancy Intense in a truly objective grade system would be given Vivid because of its much greater rarity. It is a human judgement / commercial decision - I think it is reasonable, but of course a grading system that was more truly open ended would be advantageous - just as it should be for cut grades for colourless diamonds.

hope that helps

re:Labs give Vivid to only very saturated yellows, but a pink, blue or green that might be the equivalent of yellow Fancy Intense in a truly objective grade system would be given Vivid because of its much greater rarity.

How is about blue or pink diamonds what have similar level saturation like Yellow Fancy vivid diamonds.
I think shift for blue, pink diamonds came because GIA had small ( not enough) statistic for such color. They gave vivid for best diamond what they saw decades ago.
they did not ''Changed'' it because such grade commercial reasonable. It is just hypothesis . I have not data why GIA did such system, but I see more reason in lack database then in conspiracy theory decades ago.

 

[Garry H (Cut Nut)]

Date: 7/6/2008 12:27:03 AM
Author: Serg
re:Labs give Vivid to only very saturated yellows, but a pink, blue or green that might be the equivalent of yellow Fancy Intense in a truly objective grade system would be given Vivid because of its much greater rarity.

How is about blue or pink diamonds what have similar level saturation like Yellow Fancy vivid diamonds.
I think shift for blue, pink diamonds came because GIA had small ( not enough) statistic for such color. They gave vivid for best diamond what they saw decades ago.
they did not ''Changed'' it because such grade commercial reasonable. It is just hypothesis . I have not data why GIA did such system, but I see more reason in lack database then in conspiracy theory decades ago.

Quite likley Sergey,

They did write about this in one of the G&G fancy colour articles - the pink one I think.

However your open ended system would be far more useful for the appraisal of very valuable fancy coloured diamonds.
As we know the current GIA system creates wierd price anomalies - when the market knows a Vivid is really a lucky Fancy Intense, it might be worth 20% more than a Fancy Intense that the market knows should probably have been given Vivid.

In the case of really top Vivid yellows, there could easily and fairly be a top Canary Vivid to tweet about

 

[adamasgem]

Date: 7/4/2008 8:29:37 AM
Author: Serg


Diagem,

I need remove skin in any case. Skin should not come to polish diamond.
radial color zoning you can control( measure) due semipolish process.
simply :
1)firstly you need check absorption spectrum on small windows
2) Than after you remove more material

If absorption spectrums( per length) are different you have rough with radial zoning

Think Greens Sergey, and surface radiation staining ....
Also the near surface is where the deepest color may be found on a lot of greens because of the low penetration of alpha particles..

 

[adamasgem]

Date: 7/5/2008 1:18:53 PM
Author: Serg

Diagem,

Do you know what is Munsell system? Labs us Munsell book to grade fancy color diamonds( compare diamond with piece of paper).
We build histogram of color in Munsell( blue cycles) , Luv( red cycles) systems
You can easy see how big Part Vivid, Intense, Fancy in cut depends from proportions .
Depends from Histogram we give final grade.
Task is find to proportions with best final theoretical grade.
Boundaries between color zones ( Vivid, Intense, ..) we took from Munsell , because Labs use Munsell. We slightly change boundaries in Luv color space. ( we used properties Luv color space to fix problem in boundaries what came from Munsell color system )
Of course our boundaries could be different from Labs boundaries ( Labs did not publish any standards here)
But such difference is not critical to task improve color by proportions.

Sergey The munsell system is basically taught with respect to its CIE coordinates, which are explictly defined in the literature. I think the Luv system may tend to confuse, especially with the Book of Color being used and sort of arranged to the CIE system.

 

[Serg]

Date: 7/6/2008 12:45:33 AM
Author: adamasgem

Date: 7/4/2008 8:29:37 AM
Author: Serg



Diagem,

I need remove skin in any case. Skin should not come to polish diamond.
radial color zoning you can control( measure) due semipolish process.
simply :
1)firstly you need check absorption spectrum on small windows
2) Than after you remove more material


If absorption spectrums( per length) are different you have rough with radial zoning

Think Greens Sergey, and surface radiation staining ....
Also the near surface is where the deepest color may be found on a lot of greens because of the low penetration of alpha particles..

Marty, I am working now for natural diamonds. My task support market natural diamonds. I do not like spend any efforts to support any type synthetic diamonds

 

[adamasgem]

Date: 7/5/2008 3:01:52 PM
Author: DiaGem

I still think there is more to it..., the boundaries are key..., there is too much value on the line..., and missing the thin line between the boundaries can mean ''break or make''...

You say you work mainly with yellows (I hope more is coming...), but as I said above..., when seeking the boundaries positions between the grades (light fancy, fancy, fancy intense and vivid)..., I noticed that there is a huge difference between the color intensity of a graded intense yellow vs. a intense pink or blue....

Perhaps an issue of rarity??

Much smaller sample set..

Blues and Pinks and greens also probably have more "dynamic" boundaries, that have changed or time, as I have been told in the past by a highly placed GIA researcher.

I KNOW that their colored stone system, when they had ColorMaster, had a few changes to filters and boundarys and hue definitions, based on discussions with Vince Manson.

 

[Serg]

Date: 7/6/2008 12:52:20 AM
Author: adamasgem

Date: 7/5/2008 1:18:53 PM
Author: Serg

Diagem,

Do you know what is Munsell system? Labs us Munsell book to grade fancy color diamonds( compare diamond with piece of paper).
We build histogram of color in Munsell( blue cycles) , Luv( red cycles) systems
You can easy see how big Part Vivid, Intense, Fancy in cut depends from proportions .
Depends from Histogram we give final grade.
Task is find to proportions with best final theoretical grade.
Boundaries between color zones ( Vivid, Intense, ..) we took from Munsell , because Labs use Munsell. We slightly change boundaries in Luv color space. ( we used properties Luv color space to fix problem in boundaries what came from Munsell color system )
Of course our boundaries could be different from Labs boundaries ( Labs did not publish any standards here)
But such difference is not critical to task improve color by proportions.

Sergey The munsell system is basically taught with respect to its CIE coordinates, which are explictly defined in the literature. I think the Luv system may tend to confuse, especially with the Book of Color being used and sort of arranged to the CIE system.

Marty,
what disadvantages Munsell system to grade diamonds do you know?
what limitation Munsell system do you know?
Why CIE developed Lab than Luv and then CIE97?

Munsell system has a lot of advantages and very user-friendly but very bad for diamonds just because based on reflection from paper and paint merging

Munsell is good system to grade no transparence objects only

 

[adamasgem]

Date: 7/6/2008 12:59:28 AM
Author: Serg

Date: 7/6/2008 12:45:33 AM
Author: adamasgem

Think Greens Sergey, and surface radiation staining ....
Also the near surface is where the deepest color may be found on a lot of greens because of the low penetration of alpha particles..

Marty, I am working now for natural diamonds. My task support market natural diamonds. I do not like spend any efforts to support any type synthetic diamonds

Sergey.. With all due respect, since your technical field is obviously not diamonds (and it is a second career for me) , the clasical theory is that all natural greens owe their color to natural radiation damage, mostly caused by low penetration alpha, also the cause of green skinned rough. Also some very rare blue greens.

 

[Serg]

Date: 7/6/2008 1:19:39 AM
Author: adamasgem

Date: 7/6/2008 12:59:28 AM
Author: Serg

Date: 7/6/2008 12:45:33 AM
Author: adamasgem

Think Greens Sergey, and surface radiation staining ....
Also the near surface is where the deepest color may be found on a lot of greens because of the low penetration of alpha particles..

Marty, I am working now for natural diamonds. My task support market natural diamonds. I do not like spend any efforts to support any type synthetic diamonds

Sergey.. With all due respect, since your technical field is obviously not diamonds (and it is a second career for me) , the clasical theory is that all natural greens owe their color to natural radiation damage, mostly caused by low penetration alpha, also the cause of green skinned rough. Also some very rare blue greens.

Marty, natural green diamonds are very very rare. It is not market at all for us

 

[adamasgem]

Date: 7/6/2008 1:09:12 AM
Author: Serg


Marty,
what disadvantages Munsell system to grade diamonds do you know?

How about trying to pick the area of the diamond that is the grade setting area to match with the opaque reference.

what limitation Munsell system do you know?

Well, I know you can''t reproduce all the defined high saturation colors on a CRT or on paper for one.

Why CIE developed Lab than Luv and then CIE97?To circularize the CIE system, I believe.

Munsell system has a lot of advantages and very user-friendly but very bad for diamonds just because based on reflection from paper and paint merging

I don''t see the problem, if you know what you are looking for and the key color concept of the most saturated area akin to colored stone grading.

Munsell is good system to grade no transparence objects only

I disagree. It is a scentific standard. You almost sound like GIA, wanting tke a scientifically defined standard and to twist it into something proprietary.
Look at the color naming conventions GIA bastardized.

 

[adamasgem]

Date: 7/6/2008 1:29:55 AM
Author: Serg

Date: 7/6/2008 1:19:39 AM
Author: adamasgem

Date: 7/6/2008 12:59:28 AM
Author: Serg

Date: 7/6/2008 12:45:33 AM
Author: adamasgem

Think Greens Sergey, and surface radiation staining ....
Also the near surface is where the deepest color may be found on a lot of greens because of the low penetration of alpha particles..

Marty, I am working now for natural diamonds. My task support market natural diamonds. I do not like spend any efforts to support any type synthetic diamonds

Sergey.. With all due respect, since your technical field is obviously not diamonds (and it is a second career for me) , the clasical theory is that all natural greens owe their color to natural radiation damage, mostly caused by low penetration alpha, also the cause of green skinned rough. Also some very rare blue greens.

Marty, natural green diamonds are very very rare. It is not market at all for us

That did not address my highlighted comment, but served to deflect it. Zoning and skin color go hand in hand, one can be a subset of another. While you might get X dollars for software to optimize yellows, you might get 100X for doing the pink, blue and green problem.

 

[Serg]

Date: 7/6/2008 1:39:31 AM
Author: adamasgem

Date: 7/6/2008 1:29:55 AM
Author: Serg

Date: 7/6/2008 1:19:39 AM
Author: adamasgem

Date: 7/6/2008 12:59:28 AM
Author: Serg

Date: 7/6/2008 12:45:33 AM
Author: adamasgem

Think Greens Sergey, and surface radiation staining ....
Also the near surface is where the deepest color may be found on a lot of greens because of the low penetration of alpha particles..

Marty, I am working now for natural diamonds. My task support market natural diamonds. I do not like spend any efforts to support any type synthetic diamonds

Sergey.. With all due respect, since your technical field is obviously not diamonds (and it is a second career for me) , the clasical theory is that all natural greens owe their color to natural radiation damage, mostly caused by low penetration alpha, also the cause of green skinned rough. Also some very rare blue greens.

Marty, natural green diamonds are very very rare. It is not market at all for us

That did not address my highlighted comment, but served to deflect it. Zoning and skin color go hand in hand, one can be a subset of another. While you might get X dollars for software to optimize yellows, you might get 100X for doing the pink, blue and green problem.

re:While you might get X dollars for software to optimize yellows, you might get 100X for doing the pink, blue and green problem.

Probability to sell one license for Green diamonds is 1/1000 from probability sell one license for yellow diamonds

Again main problem is possibility receive color distribution in rough. Without precise 3D color map in rough such software has zero value. You all times just ingore this problem

 

[adamasgem]

Date: 7/6/2008 1:47:17 AM
Author: Serg
re:While you might get X dollars for software to optimize yellows, you might get 100X for doing the pink, blue and green problem.

Probability to sell one license for Green diamonds is 1/1000 from probability sell one license for yellow diamonds

Again main problem is possibility receive color distribution in rough. Without precise 3D color map in rough such software has zero value. You all times just ingore this problem

I know probabilities and the cheapness of the industry However, I really don''t know how "precise" you need to be to make it usefull. I base that question on the inaccuracies of the scanners and claimed validity and usefullness of the results of a homogeneous absorption, no gletz model, which I guess has zero value also

 

[diagem]

Date: 7/6/2008 12:09:02 AM
Author: Garry H (Cut Nut)

Date: 7/5/2008 4:04:40 PM
Author: Serg


re:I noticed that there is a huge difference between the color intensity of a graded intense yellow vs. a intense pink or blue....


Labs prefer relative ( reference) grading systems. there is easy create relative grading system, you need only samples and human grade.
but problems come later. there are quiet different Vivid pink diamonds .

similar problem with ASG cut grade system. Emerald can receive ASG0 cut grade, Again problem come from relative grade.

right way is create reasonable boundaries for yellow fancy color in any uniform color system( Like Luv) , verify its on real diamonds and then use SAME boundaries for other Hue( Tone) like pink, red, blue

I will try to explain what i think each of you is saying / asking the other.

1. regional colour - the best example would be green where radiation staining is only on the outer skin. Sergey''s DiamCalc and spectrum approach will be less useful. But with arglye pink with strong colour banding / graining, combining Sergey''s software and an expert planner / polisher, there will not be problems.


2. Labs give Vivid to only very saturated yellows, but a pink, blue or green that might be the equivalent of yellow Fancy Intense in a truly objective grade system would be given Vivid because of its much greater rarity. It is a human judgement / commercial decision - I think it is reasonable, but of course a grading system that was more truly open ended would be advantageous - just as it should be for cut grades for colourless diamonds.

hope that helps

Gemological Lab''s and commercial decisions??

 

[diagem]

Date: 7/6/2008 12:36:32 AM
Author: Garry H (Cut Nut)

Date: 7/6/2008 12:27:03 AM
Author: Serg
re:Labs give Vivid to only very saturated yellows, but a pink, blue or green that might be the equivalent of yellow Fancy Intense in a truly objective grade system would be given Vivid because of its much greater rarity.

How is about blue or pink diamonds what have similar level saturation like Yellow Fancy vivid diamonds.
I think shift for blue, pink diamonds came because GIA had small ( not enough) statistic for such color. They gave vivid for best diamond what they saw decades ago.
they did not ''Changed'' it because such grade commercial reasonable. It is just hypothesis . I have not data why GIA did such system, but I see more reason in lack database then in conspiracy theory decades ago.

Quite likley Sergey,

They did write about this in one of the G&G fancy colour articles - the pink one I think.

However your open ended system would be far more useful for the appraisal of very valuable fancy coloured diamonds.
As we know the current GIA system creates wierd price anomalies - when the market knows a Vivid is really a lucky Fancy Intense, it might be worth 20% more than a Fancy Intense that the market knows should probably have been given Vivid.

In the case of really top Vivid yellows, there could easily and fairly be a top Canary Vivid to tweet about

There is..., and they are identified as Zimi''s in the trade...

Its the name of a mine located in Sierra Leone. The Zimi mine produces the most beautiful vivid yellow diamonds in the world. These diamonds consist of a deep, warm and lively yellow color..., some say they have a touch of orange...., very similar to the "Livestrong" bracelet from the Lance Armstrong Foundation!

These yellows fetch incredible prices on the market..., which shows how the markets differentiate between GIA''s Vivid grade and the Zimi Vivids...

 

[adamasgem]

Date: 7/6/2008 4:24:43 AM
Author: DiaGem


There is..., and they are identified as Zimi''s in the trade...

Its the name of a mine located in Sierra Leone. The Zimi mine produces the most beautiful vivid yellow diamonds in the world. These diamonds consist of a deep, warm and lively yellow color..., some say they have a touch of orange...., very similar to the ''Livestrong'' bracelet from the Lance Armstrong Foundation!

These yellows fetch incredible prices on the market..., which shows how the markets differentiate between GIA''s Vivid grade and the Zimi Vivids...

Probabaly Ib''s the classic "Canary" hue quite distinct from the Ia Capes. More saturated colors because of the much higher efficiency (10x to 100x) of single substitutional nitrogen (Ib''s) in creating color then N3 aggregates, the cause of color in Capes(Ia''s).