Brainstorming new innovative Diamond grading ideas:

[Serg]

Date: 11/10/2008 10:37:58 AM
Author: 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.

Karl,

"seriously affect the stone''s potential durability, or are so numerous they affect transparency and brilliance." is key point part definition I-type inclusions, where results depends from diamond size.
this part definition shift inclusions sizes( at least SI and I type) depends from diamond size

 

[oldminer]

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.
Karl

Karl;

The above quote is valid for the small diamonds GIA sends to students to do their grading training work, but it is NOT what occurs in the lab and is NOT the exact system employed by the GIA Gem Trade Laboratory for grading larger diamonds. There are so many exceptions to the above that it would be paragraphs long and still not properly cover the subject. It takes years and years of supervised experience to grade like the GIA-GTL grades diamonds. It takes just a few weeks to grade small diamonds with the sort of precision required for the GIA Diamond Course. There's a vast difference.

At one time I had hoped to bring objectivity to the definitions of clarity grading. I wrote an article calling for the creation of an SI3 standard long before anyone adopted it. My SI3 was the "eye-visible" break point for ALL diamonds. Instead SI3 became a high I1 grade and abused further the process. It was a long time ago and the trade did not find my SI3 approach palatable. The trade likes a fluid, flexible system, where there are judgment calls. Defining what size or shape diamond may or may not have an eye visible inclusions at any particular clarity grade is a real horse race bet. The variables defy objective management and it seems to be the way the lab prefers it. Since keeping all of us at their mercy for the final determination of a clarity grade suits their business model, we have been unable to break the cycle. It keeps the powerful in charge even if the job they do could be done better. I have grown used to what the GIA-GTL does and have no problem with using the status quo approach. Making sense of it and writing it down to teach others is extremely problematic. It keeps us dependent and it is slowing down objective progress. We can do much better, but who wants to go first?

 

[Garry H (Cut Nut)]

Date: 11/10/2008 7:45:29 AM
Author: DiaGem

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



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

Here is a 1/2 and 5ct very slightly tinted example - (I made the 1/2ct bigger on the screen - it does not change the color DG)

I am not exaggerating.

 

[Garry H (Cut Nut)]

oops

 

[strmrdr]

Date: 11/10/2008 4:10:00 PM
Author: oldminer
We can do much better, but who wants to go first?

As I have said before the only thing that is going to change anything is government intervention.

 

[diagem]

Date: 11/10/2008 8:15:00 PM
Author: Garry H (Cut Nut)

Date: 11/10/2008 7:45:29 AM
Author: DiaGem

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



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

Here is a 1/2 and 5ct very slightly tinted example - (I made the 1/2ct bigger on the screen - it does not change the color DG)

I am not exaggerating.

I am sorry Garry..., I think you lost me or I lost you..., dont get your saying...

 

[Garry H (Cut Nut)]

Date: 11/11/2008 12:09:07 AM
Author: DiaGem

Date: 11/10/2008 8:15:00 PM
Author: Garry H (Cut Nut)

Date: 11/10/2008 7:45:29 AM
Author: DiaGem

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



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

Here is a 1/2 and 5ct very slightly tinted example - (I made the 1/2ct bigger on the screen - it does not change the color DG)

I am not exaggerating.

I am sorry Garry..., I think you lost me or I lost you..., dont get your saying...

Can you see a colour difference?
it comes from the size alone

 

[strmrdr]

This shows it a little better,,,,
What Garry is saying is that if you take a 1mm slice of the material it is the same color from both.
What DiaGem is saying is color zoning happens and you might be able to cut a .5t D out of a J 5ct which is also true.

 

[diagem]

Date: 11/11/2008 1:13:18 AM
Author: Garry H (Cut Nut)

Date: 11/11/2008 12:09:07 AM
Author: DiaGem

Date: 11/10/2008 8:15:00 PM
Author: Garry H (Cut Nut)

Date: 11/10/2008 7:45:29 AM
Author: DiaGem

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



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

Here is a 1/2 and 5ct very slightly tinted example - (I made the 1/2ct bigger on the screen - it does not change the color DG)

I am not exaggerating.

I am sorry Garry..., I think you lost me or I lost you..., dont get your saying...

Can you see a colour difference?
it comes from the size alone

No..., i dont...

 

[Garry H (Cut Nut)]

buy a new computer or monitor

 

[diagem]

Date: 11/11/2008 5:38:07 AM
Author: Garry H (Cut Nut)
buy a new computer or monitor

Why..., you see a difference....?........?

 

[oldminer]

Even assuming there is no color zoning present, a 1 carat H master diamond is visually a lighter color (tone) than a 5 carat GIA H color graded diamond. The images Garry supplied show the larger diamond to be darker in appearance in both images. You should be able to see it although it is not an impressive difference. Put the images into photoshop and use a "magic wand" to define the colors in idential places. You''ll see the larger diamond is darker by a little. This is an illogical and highly unusual color grading system. It makes sense only because of the unique nature and high value of diamonds. Keeping in mind the concept that changing the system will make it extremely difficult to get users on board, we have struggled to make technology mimic the existing GIA system. In time, there will be early adopters.

The issue of color zoning having radical effects on color in certain locations of diamonds further plays with the problem solving issue. The position and effect of the color zoning is unique in each diamond just as what the zone does after cutting to have an effect on visible overall color. This does raise further issues which will need to be addressed. I think this falls into the rarer exceptions category, but possibly it is more common than I think it may be. Transparency, visible UV fluorescence, inclusions, facet arrangment, proportions,and color zoning all come into play with diamond color grading. Not an easy topic to squeeze into a simple formula.

 

[diagem]

Date: 11/11/2008 7:38:59 AM
Author: oldminer
Even assuming there is no color zoning present, a 1 carat H master diamond is visually a lighter color (tone) than a 5 carat GIA H color graded diamond. The images Garry supplied show the larger diamond to be darker in appearance in both images. You should be able to see it although it is not an impressive difference. Put the images into photoshop and use a ''magic wand'' to define the colors in idential places. You''ll see the larger diamond is darker by a little. This is an illogical and highly unusual color grading system. It makes sense only because of the unique nature and high value of diamonds. Keeping in mind the concept that changing the system will make it extremely difficult to get users on board, we have struggled to make technology mimic the existing GIA system. In time, there will be early adopters.

Always? on what shape? in the face-up position or all positions?
Dave..., I know its much of a consensus that the larger Diamonds are darker..., but I think its subjective to who grades the Diamonds too. I can say with security (based on my experience) that it not always the case..., but again..., I see subjectivity as the main problem...
BTW..., I cant see the difference between both the Diamonds Garry posted..., they look identical to me. Should I have seen the difference?

The issue of color zoning having radical effects on color in certain locations of diamonds further plays with the problem solving issue. The position and effect of the color zoning is unique in each diamond just as what the zone does after cutting to have an effect on visible overall color. This does raise further issues which will need to be addressed. I think this falls into the rarer exceptions category, but possibly it is more common than I think it may be. Transparency, visible UV fluorescence, inclusions, facet arrangment, proportions,and color zoning all come into play with diamond color grading. Not an easy topic to squeeze into a simple formula.

I dont think the color zoning you and Karl mentioned is what I am talking about...
What I am saying is:

If you take a tinted (J) perfect octahedron crystal rough..., saw it smack in the middle..., you will end up (most of the times) with two lighter shaded pyramids (1/2 octahedron)..., probably a shade or sometimes even two shades lighter (especially in the darker tones)..., say "I" or maybe even "H".

(like my highlighted part above..., there are way too many factors that will/can influence color behaviour in the Diamond''s material when altered)

Now..., take that same octahedron (J) Diamond and saw a 15-25% top off..., you end up with a 3/4 sawed octahedron and a small pyramid (as the 15-25% top).
Not because of "color zoning"..., that 15-25% top can (and probably will be most of the time) a few shades significantly lighter than the 3/4 sawed octahedron.
It can easily result in a 75% sawed octahedron that stayed a "J" color vs. the 15-25% pyramid top that is now an F-G color!

I hope I just clarified what I wrote earlier....

 

[oldminer]

DiaGem:

What you are saying is understandable. You are showing that many substantial reasons exist which prevent accurate color grading until a final diamond is fully cut. Grading rough helps a cutter understand the range of color in the roiugh, but won''t dictate what color or colors the finished stone(s) end up. No problem.

My basis is that color grading should be done to the final diamond in all cases and not based on anything but the Actual Color of the end product. We can eventually come to a standard conclusions about whether the color will be face-up or from the side. We may still want to grade fancy colors face-up and near colorless stones from the side. I''d prefer the entire process to become face-up for every diamond, but we all know there would be huge financial consequences to such a shift in standards. This would lead to huge resistance to change and I am more for positive, incremental change than completely painful change at any cost. This change in grading needs to be so palatable and tempting that users will want it to happen. If any organization thinks it can force a change which creates havoc, they might just find they don''t have the power to overcome the resistance to it. No organization currently in a position of power has absolute authority over the rest of us. It would be wrong headed to pursue huge change unless the end users really want it to become a new standard.

 

[diagem]

Date: 11/11/2008 5:02:38 PM
Author: oldminer
DiaGem:

What you are saying is understandable. You are showing that many substantial reasons exist which prevent accurate color grading until a final diamond is fully cut. Grading rough helps a cutter understand the range of color in the roiugh, but won''t dictate what color or colors the finished stone(s) end up. No problem.

My basis is that color grading should be done to the final diamond in all cases and not based on anything but the Actual Color of the end product. We can eventually come to a standard conclusions about whether the color will be face-up or from the side. We may still want to grade fancy colors face-up and near colorless stones from the side. I''d prefer the entire process to become face-up for every diamond, but we all know there would be huge financial consequences to such a shift in standards. This would lead to huge resistance to change and I am more for positive, incremental change than completely painful change at any cost. This change in grading needs to be so palatable and tempting that users will want it to happen. If any organization thinks it can force a change which creates havoc, they might just find they don''t have the power to overcome the resistance to it. No organization currently in a position of power has absolute authority over the rest of us. It would be wrong headed to pursue huge change unless the end users really want it to become a new standard.

I agree with every word you wrote...., I personally dont see how face-up grading "ONLY" will be better or even more accurate...
I dont have problem with change..., when it make pure sense..., this shift doesnt make sense because we cant limit or eliminate the subjectivity involved in grading color or even clarity as far as I can see future-wise...

I dont see (and have not seen) any potential plans, new tech., or other gizmos that can accurately and consistently measure the grades with no human intervention...

I know Peter Meeus (formerly from HRD) is heading this relative new Lab called IDL out of Dubai claiming to grade colorless Diamonds via their "ground-breaking" technology..., the fully automated TradeMarked "IDL color meter"..., IDL also claims "100% consistent manner" in their color grading capabilities.

I have yet seen a Diamond graded by IDL...

I am not saying its not possible as I dont know what the future has planned for us...., but as as today I dont see that humans can be replaced...