grading approach for fancy colors vs M-Z round brilliants?

[diamondhoarder]

According to the tutorial on pricescope:

"Fancy Color begins beyond the grade Z in the color grading scale. While colorless, near colorless, faint and light diamond colors are graded from the face-down position. Laboratory graders assess fancy color diamonds from the face-up or top view of the diamond."

My question is, how do graders decide whether the diamonds should be graded as a fancy color or as a faint/ light color (ie whether to grade them face down or face up)?

I have been looking at some light yellow and brown diamonds in the U - Z range and I have noticed that especially in round brilliant cut, these often to seem to face up lighter than when they are viewed sideways on through the pavillion or face down? I think this might be because of the larger amount of white light returned by a brilliant cut when viewed face up than by other fancy cuts. I was wondering whether a situation could exist with a light yellow or light brown colored diamond where, graded face down they are darker than Z color (so possibly in the fancy range) but when graded face up they don't qualify as a fancy diamond because the color has been toned down as a result of the white light return from the round brilliant cut?

 

[diamondhoarder]

Re: grading approach for fancy colors vs M-Z round brilliant

According to the tutorial on pricescope:

"Fancy Color begins beyond the grade Z in the color grading scale. While colorless, near colorless, faint and light diamond colors are graded from the face-down position. Laboratory graders assess fancy color diamonds from the face-up or top view of the diamond."

My question is, how do graders decide whether the diamonds should be graded as a fancy color or as a faint/ light color (ie whether to grade them face down or face up)?

I have been looking at some light yellow and brown diamonds in the U - Z range and I have noticed that especially in round brilliant cut, these often to seem to face up lighter than when they are viewed sideways on through the pavillion or face down? I think this might be because of the larger amount of white light returned by a brilliant cut when viewed face up than by other fancy cuts. I was wondering whether a situation could exist with a light yellow or light brown colored diamond where, graded face down they are darker than Z color (so possibly in the fancy range) but when graded face up they don't qualify as a fancy diamond because the color has been toned down as a result of the white light return from the round brilliant cut?

Rockdiamond or other FCD experts - could you comment on this please?

 

[kenny]

Re: grading approach for fancy colors vs M-Z round brilliant

I'm going to get beat up for phrasing it this way but IMO the 'attractiveness' of the color determines whether GIA grades a diamond on their FCD scale or their D-Z scale.

Not fair.
Not scientific.
Not a very nice thing to say for owners who love their S-graded diamonds.
But there you go.
Again, just my opinion.

This is not my opinion though, when it comes to FCD grading GIA is the 10-ton gorilla and they do whatever they want.

 

[Karl_K]

Re: grading approach for fancy colors vs M-Z round brilliant

Your not that far off Kenny.
They look at it face up and if in the graders opinion it meets the requirement for fancy it is graded as such if not it is flipped over and graded on the regular color grading scale.

 

[diamondhoarder]

Re: grading approach for fancy colors vs M-Z round brilliant

Interesting.........

So would I be right in thinking that if there are additional color hues (eg i bit if orange or a bit of pink) in a tinted yellow or brown stone that this would not even be mentioned if it gets graded N-Z?

 

[kenny]

Re: grading approach for fancy colors vs M-Z round brilliant

Interesting.........

So would I be right in thinking that if there are additional color hues (eg i bit if orange or a bit of pink) in a tinted yellow or brown stone that this would not even be mentioned if it gets graded N-Z?

Even a bit of pink or orange puts it in the FCD pile.

The 3 'hues' that do not assure FCD status are brown, yellow and gray, though GIA classifies SOME brown, yellow and gray diamonds as FCDs.
Again, I think it is all about the attractiveness of the brown, yellow or gray.

In today's PC climate of not wanting to hurt anyone's feelings I doubt GIA would admit it is subjective.
They'll have some carefully-worded mumbo jumbo to save face.

 

[Rockdiamond]

Re: grading approach for fancy colors vs M-Z round brilliant

This is a really good and interesting subject. Without a doubt it is very difficult to grade the colors that have more shade then M. For this reason there is just less consistency.
Having looked at thousands and thousands of stones my experience is just based on looking at the results. Maybe someone more familiar with GIA grading tech Methodology and technique will explain the nuts and the bolts of why – I can only speak to what the results are.


Based on the difficulty of grading the shades there is plenty of crossover. That is to say there are examples of stones grated Y to Z color that will be darker than the other stones which of been graded fancy light yellow.

I seriously doubt GIA graders use "attractiveness" in their deliberations on color grading. It's just a matter of how much yellow is in the diamond.
As far as what you or anyone else finds attractive – it makes sense to look if you can. Given the subtle shade differences as compared to the larger price differences buyers who like the lighter yellows are getting huge values in my opinion.

 

[diamondhoarder]

Re: grading approach for fancy colors vs M-Z round brilliant

[I seriously doubt GIA graders use "attractiveness" in their deliberations on color grading. It's just a matter of how much yellow is in the diamond.[/quote]

So when the GIA graders consider how much yellow or brown is in the diamond, what lighting conditions do they base this on? I find this particularly interesting because I have been looking at light and fancy light brown diamonds and have noticed such a variation in the depth and hue of color depending on lighting conditions - more so than some of the yellow diamond I have seen.

 

[Rockdiamond]

Re: grading approach for fancy colors vs M-Z round brilliant

I just noticed that the title of this thread involves round diamonds. That makes it even more challenging for the grader.
The reason is how much color the different shapes project. A round diamond is very good at projecting white light. For this reason many round stones that look quite yellow through the back look pale from the front.
Brown is a different story due to the way the color is projected. Many ( most) brown diamonds use the grain of the diamond to project the color.
That, and the fact that the color brown is a stronger color than yellow make brown round diamonds more common than yellow.

 

[cflutist]

Re: grading approach for fancy colors vs M-Z round brilliant

There is a very interesting article that I read recently about the Characterization and Grading of Natural-Color Yellow Diamonds in GIA's publication Gems & Gemology - Summer 2005 issue.

There is a downloadable .pdf file.

I don't know if this link works. If not, just Google Gems and Gemology Yellow diamonds.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=3&ved=0CF0QFjAC&url=http%3A%2F%2Fwww.gia.edu%2Fcs%2FSatellite%3Fblobcol%3Dgfile%26blobheader%3Dapplication%252Fpdf%26blobheadername1%3DContent-Disposition%26blobheadername2%3DMDT-Type%26blobheadername3%3DContent-Type%26blobheadervalue1%3Dattachment%253B%2Bfilename%3DSU05.pdf%26blobheadervalue2%3Dabinary%253B%2Bcharset%3DUTF-8%26blobheadervalue3%3Dapplication%252Fpdf%26blobkey%3Did%26blobtable%3DGIA_DocumentFile%26blobwhere%3D1355954814305%26ssbinary%3Dtrue&ei=je8eVO-UD6rsigLNtoDoCA&usg=AFQjCNEdtEB0U6xmRfft5FCtN-3o7Lam8A&sig2=jHtzaW_5hHC-PkX-VwC_zA&bvm=bv.75775273,d.cGE

 

[diamondhoarder]

Re: grading approach for fancy colors vs M-Z round brilliant

There is a very interesting article that I read recently about the Characterization and Grading of Natural-Color Yellow Diamonds in GIA's publication Gems & Gemology - Summer 2005 issue.

There is a downloadable .pdf file.

I don't know if this link works. If not, just Google Gems and Gemology Yellow diamonds.

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=3&ved=0CF0QFjAC&url=http%3A%2F%2Fwww.gia.edu%2Fcs%2FSatellite%3Fblobcol%3Dgfile%26blobheader%3Dapplication%252Fpdf%26blobheadername1%3DContent-Disposition%26blobheadername2%3DMDT-Type%26blobheadername3%3DContent-Type%26blobheadervalue1%3Dattachment%253B%2Bfilename%3DSU05.pdf%26blobheadervalue2%3Dabinary%253B%2Bcharset%3DUTF-8%26blobheadervalue3%3Dapplication%252Fpdf%26blobkey%3Did%26blobtable%3DGIA_DocumentFile%26blobwhere%3D1355954814305%26ssbinary%3Dtrue&ei=je8eVO-UD6rsigLNtoDoCA&usg=AFQjCNEdtEB0U6xmRfft5FCtN-3o7Lam8A&sig2=jHtzaW_5hHC-PkX-VwC_zA&bvm=bv.75775273,d.cGE

Yes the link works

That is the most comprehensive information about grading of yellow diamonds ever!

 

[cflutist]

Re: grading approach for fancy colors vs M-Z round brilliant

You are welcome.

There is also a similar article for:

Pinks - Summer 2002

and

Type IIB Blues - Winter 1998

Happy reading.

 

[diamondhoarder]

Re: grading approach for fancy colors vs M-Z round brilliant

I don't suppose you came across one for browns? I tried searching on it through google but no success so far

 

[cflutist]

Re: grading approach for fancy colors vs M-Z round brilliant

No I did not, just those three.

 

[diamondhoarder]

Re: grading approach for fancy colors vs M-Z round brilliant

Thanks everyone for your comments and links to articles, very informative. That will keep me busy for a while

 

[Sunstorm]

Re: grading approach for fancy colors vs M-Z round brilliant

Great link, thanks! Now I cannot wait to read the article and the whole issue and will search for the other articles you mentioned.

It is a very interesting theory that colors are graded based on how attractive they are. I think there has to be some truth to this as most the time I see faint, very light or even light browns being graded on the letter scale and we know that brown in general is not desirable. Yet, when it comes to pinks even very faint pinks will be graded as FCDs, even when the color is hardly discernible.

That said, this gives rise to many problems and inconsistencies but we know that they are there. I mean how is it decided if a certain yellow is desirable. Also, I have run into problems with GIA grades, I have a fancy brownish yellow has a color that is in part leaning towards deep but is at least intense in saturation yet it is graded simply as fancy, why because of the brown? I am told that GIA has gotten much stricter recently but I do not see this in every case, I think what it may be is again that brown is considered unattractive, this could explain it. It would be very interesting to have the stone regraded but who knows what result we would get, it could be totally different this time yet I am absolutely positive that the color grade is incorrect. Many of us have been there. Then one may start wondering how meaningful a report really is. I do not want to say it is just a piece of paper as with FCDs it is very important to know that the color is of natural origin and it is also important to know that a diamond is not synthetic but the inconsistencies are certainly very concerning.

We also often get grading results where a modifier is not on the report but who decides if a modifier is strong enough to be put on the paper? Many yellows are rarely pure yellows, there is very often a bit of green, a bit of orange and/or a bit of brown, or some or all of the above. I am very color sensitive though and may see something that others do not.

Cool thread on one of my favorite subjects.)

 

[Rockdiamond]

Re: grading approach for fancy colors vs M-Z round brilliant

I agree – excellent article and thank you for the link!
Actually GIA does note the presence of faint Brown in stones ranging from maybe H on upward. In terms of dealers complaining about GIA, that's a very old story.
If a dealer is so sure GIA made a mistake, they can resubmit the diamond.

The color of "fancy brownish yellow" is one of the widest colors I've ever seen. I've seen stones with this color grade that look quite brown, quite yellow, quite orange, and even green.
The reason is that the brown – ISH modifier can take many forms. Then when it interacts with the yellow it's an open book of results.
Fancy brown yellow is a more consistent shade.

At the end of the day "attractiveness" is decided by the market. A stone with a grade of fancy brownish yellow that's lively with a bright color will sell for a lot more than a stone that looks dull with the same color grade.
This can be a huge advantage to people that find things attractive that the market devalues… Such as a diamond rated S-T color.

 

[Sunstorm]

Re: grading approach for fancy colors vs M-Z round brilliant

Thank you for your input Rockdiamond, this makes sense about GIA, perhaps the reason I did not notice this is because the stones that had quite a bit of brown that I was talking about were graded by European labs and not GIA. One particular stone was definitely a very light brown at least but graded on the letter scale. It is true that dealers complain about GIA but I think it is not just GIA that dealers complain about but the inconsistencies that exist within labs or between labs. Sometimes they are right and sometimes not.

It is also possible that as you said brownish yellows can take many forms, a warmer brownish that is almost orange and a cooler brownish that is almost greenish or grayish, etc. The range is really wide and some with a brown modifier are very attractive while some may not be. I certainly have not seen as many FCDs as you have. For me it is probably not worth resubmitting at this point as it is not so important where I am and my jewelry finds new owners locally, when I can part with them.) It has also already been made into jewelry.

Hope this thread continues. Now I really want to find the articles on pinks and blues.

 

[cflutist]

Re: grading approach for fancy colors vs M-Z round brilliant

Here you go (download the .pdf):

http://www.gia.edu/gems-gemology/summer-2002-grading-natural-pink-diamonds-king

http://www.gia.edu/gems-gemology/winter-1998-blue-diamonds-king

 

[WinkHPD]

Re: grading approach for fancy colors vs M-Z round brilliant

I just noticed that the title of this thread involves round diamonds. That makes it even more challenging for the grader.
The reason is how much color the different shapes project. A round diamond is very good at projecting white light. For this reason many round stones that look quite yellow through the back look pale from the front.
Brown is a different story due to the way the color is projected. Many ( most) brown diamonds use the grain of the diamond to project the color.
That, and the fact that the color brown is a stronger color than yellow make brown round diamonds more common than yellow.

I constantly hear this about rounds, yet remember vividly seeing a collection of colored EightStar cut diamonds. All of them were incredibly bright diamonds with rich saturated colors, including a strong blue color and some wonderful yellows along with some other diamonds of various colors.

I did not get to see the original diamonds, but Richard von Sternberg, the cutter, insisted that they lost none of the original depth of color when they were faceted to the EightStar cut quality.

It leaves me wondering how much of the color is dissipated in a poorly cut round versus maintained in a well cut round?

One would need a MUCH bigger wallet than mine to experiment with this conjecture. I do know for sure though, that you can have an incredible deeply colored diamond in a round, even though it is much more traditional to cut them in rectangular or oval shapes.

Wink

 

[WinkHPD]

Re: grading approach for fancy colors vs M-Z round brilliant

Thank you Cheryl for the links to these informative articles!

Wink

 

[cflutist]

Re: grading approach for fancy colors vs M-Z round brilliant

I just noticed that the title of this thread involves round diamonds. That makes it even more challenging for the grader.
The reason is how much color the different shapes project. A round diamond is very good at projecting white light. For this reason many round stones that look quite yellow through the back look pale from the front. Brown is a different story due to the way the color is projected. Many ( most) brown diamonds use the grain of the diamond to project the color.
That, and the fact that the color brown is a stronger color than yellow make brown round diamonds more common than yellow.

Wow, I guess I am really fortunate to have a bracelet made of .20s FIY rounds then

 

[Sunstorm]

Re: grading approach for fancy colors vs M-Z round brilliant

I have round fancy vivid yellows but they are small, starting from 1 mm melee up to 10 pointers right now. I think that it is hard to find rounds in larger sizes, yes I am sure you are right Wink that they are around but not so common and they had top even color to begin with. I would certainly love to have some but have never seen FCDs in larger sizes and ideal RBs. Again my experience is still somewhat limited of course so others have probably seen more of them. A fancy vivid yellow ideal RB would probably be my holy grail although a top cut cushion is still on my list, one of those chunky faceted ones.)

 

[Rockdiamond]

Re: grading approach for fancy colors vs M-Z round brilliant

I just noticed that the title of this thread involves round diamonds. That makes it even more challenging for the grader.
The reason is how much color the different shapes project. A round diamond is very good at projecting white light. For this reason many round stones that look quite yellow through the back look pale from the front. Brown is a different story due to the way the color is projected. Many ( most) brown diamonds use the grain of the diamond to project the color.
That, and the fact that the color brown is a stronger color than yellow make brown round diamonds more common than yellow.

Wow, I guess I am really fortunate to have a bracelet made of .20s FIY rounds then

ABSO-FREAKIN-LUTELY!!!

I love Fancy Colored round diamonds.....I'd love to see your bracelet one day.
For sure it's an incredibly rare piece.

Wink- For sure when a cutter manages to hit a "sweet spot" in terms of Polish Symmetry/ Table and depth, the stone may bring a premium- but the fact that color is king in FCD's does lead cutters to use some "strange combos"
One amazing thing about Fancy Colored Rounds is that they show how "badly" a diamond can be cut ( if you're measuring them using a colorless cut as a yardstick) yet still be remarkably bright and have great light performance.
For example, I've seen amazing round FCD's with depths as deep as 65%- some have very heavy girdles. The table can get up to 65%.
Sometimes you can see an aspect to the cut that might be a problem in a colorless, but it's hidden by the cut.
But there's plenty of cases where these unorthodox combos manage to perform with no excuses.

I do believe I've seen that 8star picture you mention- and yes, it was spectacular.

OVincze - I know what you mean- many times the smaller natural yellow round diamonds ( .02 and down) have very strong color. It's rare that melee shows "pure" yellow- many times I find it's tinged with orange.
I love lighter yellow melee- say equivalent to a Y-Z- but it's actually harder to find than the intense melee.

 

[Karl_K]

Re: grading approach for fancy colors vs M-Z round brilliant

I constantly hear this about rounds, yet remember vividly seeing a collection of colored EightStar cut diamonds. All of them were incredibly bright diamonds with rich saturated colors, including a strong blue color and some wonderful yellows along with some other diamonds of various colors.

I did not get to see the original diamonds, but Richard von Sternberg, the cutter, insisted that they lost none of the original depth of color when they were faceted to the EightStar cut quality.

It leaves me wondering how much of the color is dissipated in a poorly cut round versus maintained in a well cut round?

One would need a MUCH bigger wallet than mine to experiment with this conjecture. I do know for sure though, that you can have an incredible deeply colored diamond in a round, even though it is much more traditional to cut them in rectangular or oval shapes.

Wink

It is my understanding that the natural color of the diamond has to be absolutely in the sweet spot to work in a round. Hence they are rarer and more $$$.
Where a radiant fancy light may be as low as the q range when graded face down and in some cushion designs down into the u range.

 

[WinkHPD]

Re: grading approach for fancy colors vs M-Z round brilliant

I just noticed that the title of this thread involves round diamonds. That makes it even more challenging for the grader.
The reason is how much color the different shapes project. A round diamond is very good at projecting white light. For this reason many round stones that look quite yellow through the back look pale from the front. Brown is a different story due to the way the color is projected. Many ( most) brown diamonds use the grain of the diamond to project the color.
That, and the fact that the color brown is a stronger color than yellow make brown round diamonds more common than yellow.

Wow, I guess I am really fortunate to have a bracelet made of .20s FIY rounds then

<Snip>
I do believe I've seen that 8star picture you mention- and yes, it was spectacular.

<Snip>

The picture was nice, but playing with those diamonds was WAY fun.

Wink

 

[WinkHPD]

Re: grading approach for fancy colors vs M-Z round brilliant

Thanks Karl, that is good to know.

Wink

 

[Rockdiamond]

Re: grading approach for fancy colors vs M-Z round brilliant

Karl- in my experience, there's no difference in performance or color retention between FCD Cushion and Radiant Cuts. The two designs are both so variable there's plenty of cases where the only difference is the outline of the diamond.
In terms of rounds- it really depends on what the body color of the stone is. Weight retention also plays a role.

We did have a case of an S-T cushion which was damaged during setting the had to be recut.
We lost about 15% of the weight, and the stone re-cut to a Fancy Yellow Radiant.
S-T to FY, it was an amazing transformation.



Wink you saw them in person??
Wow.

 

[cflutist]

Re: grading approach for fancy colors vs M-Z round brilliant

Does anyone have a picture of these FC 8-Stars?
I would love to see them.

 

[Sunstorm]

Re: grading approach for fancy colors vs M-Z round brilliant

I completely agree Rockdiamond, I tried out the 1 mm vivid yellow melee and I do not think they work as well, not sure why that is. The ten pointers are nice and can be used in the center of a design or for a tennis bracelet or earrings but I too think that lighter yellows are better as melee. But then I have to say I have a soft spot for lighter lemony yellows.

What about the sweet spot theory? I have heard that as well or the rough has to be so evenly colored and saturated that it can be cut into a round?

I have not seen that picture so either I am blind and braindead tonight not reading this thread thoroughly or just do not know where to find it.