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Are faint colors such as U-V., W-X, and Y-Z "Fancy Colored Diamonds
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Sometimes I feel it''s very subjective especially when a lab grades a diamond "Y-Z."
I''ve seen both very brown and very yellow diamonds graded as "Y-Z."
www.metrojewelryappraisers.com
I''ve seen both very brown and very yellow diamonds graded as "Y-Z."
www.metrojewelryappraisers.com
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Hi Kenny!
Thanks for joining in!
Great question.
To my knowledge, GIA is kind of cagey about exactly the methodology used to grade the "split letter" grades.
It also brings up another important point.
If GIA grades a diamond in the face up position,isn''t that actually more relevant than a table down view?
A case could be made that how a diamond looks through the pavilion is not nearly as important as it''s face.
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Interesting Jeff!
It brings up yet another important point- different labs, and how they grade.
If we compare this to colorless, it''s an even more "one pony" game- as AGS rarely sees colored diamonds.
IMO, this leaves GIA as the only viable report here in the US.
In terms of brown, if GIA sees it, they note it, from my experience.
We''ve had stones that came back L and still had GIA note "Faint Brown" on the report.
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No no no.
I mean how does GIA decide if it is a fancy yellow OR a diamond they will place on the TUVWXYZ scale?
What is it about the quality of yellow that decides. (This is exactly what I'm asking for a pic of [worth a thousand words].)
I've been asking this exact same question over and over in the last few days.
No answer yet.
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Next question.
When diamond owner, cutter or seller, sends a borderline diamond to GIA that may come back fancy-colored or TUVWXYZ to GIA do they cross their fingers, say a prayer and submit it requesting a fancy color report, which GIA either gives or does not give?
Or do they just send it to GIA, without specifying which category they expect, and let them decide if it falls in the fancy color category or the TUVWXYZ category, and accept GIA's decision.
When diamond owner, cutter or seller, sends a borderline diamond to GIA that may come back fancy-colored or TUVWXYZ to GIA do they cross their fingers, say a prayer and submit it requesting a fancy color report, which GIA either gives or does not give?
Or do they just send it to GIA, without specifying which category they expect, and let them decide if it falls in the fancy color category or the TUVWXYZ category, and accept GIA's decision.
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Next question, RD.
In another thread you wrote this.
Quote:
There was one time a cutter friend of mine showed me the most beautiful 4 and a half carat yellow emerald cut and asked me what I would grade the color.
I saw it as "fancy Light Yellow"- and he agreed, but would not let me buy he diamond.
Why?
"Do you know how much more a 4ct Fancy Yellow Radiant is worth compared to a 4 and half ct fancy Light Yellow Emerald cut?", he asked. Yes, I sadly answered.
Next time I saw the stone it was a (gorgeous) radiant.
End quote
I got it.
Light bounces back and forth through the yellow material more times in a radiant than in an emerald cut, hence the radiant results in stronger color from the same rough.
Makes sense.
Now my question.
Can this cut-dependent-color-factor also affect whether a diamond falls into the TUVWXYZ zone or the fancy colored zone?
IOW can an owner get a GIA Y/Z grade, then recut it to get a GIA fancy color grade?
Or is the fancy color category not about the strength of the color, but rather the hue itself?
In another thread you wrote this.
Quote:
There was one time a cutter friend of mine showed me the most beautiful 4 and a half carat yellow emerald cut and asked me what I would grade the color.
I saw it as "fancy Light Yellow"- and he agreed, but would not let me buy he diamond.
Why?
"Do you know how much more a 4ct Fancy Yellow Radiant is worth compared to a 4 and half ct fancy Light Yellow Emerald cut?", he asked. Yes, I sadly answered.
Next time I saw the stone it was a (gorgeous) radiant.
End quote
I got it.
Light bounces back and forth through the yellow material more times in a radiant than in an emerald cut, hence the radiant results in stronger color from the same rough.
Makes sense.
Now my question.
Can this cut-dependent-color-factor also affect whether a diamond falls into the TUVWXYZ zone or the fancy colored zone?
IOW can an owner get a GIA Y/Z grade, then recut it to get a GIA fancy color grade?
Or is the fancy color category not about the strength of the color, but rather the hue itself?
glitterata
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Kenny, this question was addressed in this thread. The answer given there was yes, cut can definitely affect whether a diamond falls in the end-of-the-alphabet zone or the fancy color zone, which is one reason there are so few low-alphabet ideal-cut round brilliants for sale.
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Hi Kenny,
If I have the phots at hand, I'm only to glad to post them, when time allows.
My photos are usually taken in the "face up" position.
I generally use photos of items that have been sold so I donlt have them here for additonal viwes
Let's start even even above the "split letter" scale. The stone in the photo was graded M by GIA.
kenny has grouped T-Z one broad grade. In some ways, that's not all that far from the truth, in my experience.
For one thing, it's far easier to judge the absense of color, as opposed to the presence of color.
Easier( in a way) to grade the difference btween D and E than S-T, and U-V- both of which look pretty darn yellow. Even the M in the photo- whcih really does face up that way- had a lot of color.
But once the color starts to shore up, it again becomes easier. Calling the difference between W-X, to Y-Z is a lot easier than S-T and U-V.
The answer to how GIA decides whether to grade the diamond "Face Up" or throug the pavillion is, I believe somethign GIA does not really divulge.
YOu're asking about the quality of the yellow color- and that is a great question,
BUt the wqord quality cold mean different things here.
"Purity" for example.
My experince is that the face up of W-X is generally lighter than than of Y-Z. The face up of Y-Z is generally lighter than that of Fancy Light Yellow.
For this reason it's always seemed to me that GIA does include a face up grading position for these colors- because it's not always the same from the pavillion.
ETA: Sorry I',m a few posts and quesitons behind. I'll answer all.
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Time for one or two more...
Another good question kenny.
No, you can not tell GIA what to do.
I mean,you can, but it won't make a difference.
no matter what you write on the parcel paper, they grade it the same way.
That includes weight- sometimes you loose or gain a point due to scale variations.
Again, it makes no difference what weight you write on the paper.
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Kenny, these are all great questions.
In terms of re-cutting: yes that does go one. if a cutter feels he's more expert than the one who cut a particular stone, they may recut and resubmit.
BUT- and it's a big but- this does not hold true in every case. In fact it's rather rare nowadays.
As I've said- it really dos not matter what you tell them.
In terms of cut- a really "poorly" cut stone- by colorless stone standards- can- and do- get some of the loftiest GIA color grades.
AS I've also said- my experience is that, in general, Y-Z faces up darker than W-X , which faces up darker than U-V, leading me to believe that GIA's grading down there is heavily influenced by Face Up grading.
Therefore a smart cutter is going to cut for good face up color.
Which is why some really well cut Radiant Cut exist in these colors.
I've recently seen a Fancy Light Yellow which was surely graded by asomeone who was angry that day ( it seems) I mean it rally looked like a Fancy Yellow.
It was Internally Flawless, and EX/EX. You can bet you bottom dollar the cutter resubmitted.
I saw the stone, and it was priced like a Fancy light yellow. The cutter was crying.
It was by no means an inexpensive Fancy Light Yellow- but it was quite a bit less than a Fancy Yellow.
The same thing happens at the Y-Z, FLY borderline.
My experience is that the finer stones in terms of cut, and overall characteristics are where the cutters take their lumps and accept the GIA U=V, W-X and Y-Z grades. They can still find buyers at a somewhat reasonable price.
IN many cases, the poorly cut ones in the borderline of UV-FLY go to the sub par labs.
Not to say many poorly cut ones don't go to GIA as well.
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HI all,
Kenny, I''ve been thinking about the recut issue.
Although I don''t believe it''s possible to continually re-submit stones to GIA and get better grades, cutters do recut stones to get better grades from GIA.
Sometimes even one facet can make a difference between Vivid and Intense...or a Y-Z and a Fancy Light.
In these lighter shades the prices are so much lower that it makes less sense.
If it''s a 5.00 Intense, that can be improved to a Vivid a cutter might re-submit, and continue to work on the stone for weeks.
This goes to your question, as the cut does make a difference in perceived color.
The stone in the photo was graded U-V by GIA.
It''s also a good example to use as it might have been a candidate for a recut. But, to recut effectively, the stone must be have certain characteristics. This one was not considered improvable.
In terms of the color of a U-V, it''s a pretty good example.
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Great point Diagem!
The pear shape from a few posts above, for example, an M color- is cut using methods for colorless diamonds.
The cutter is probably trying to achieve a "white looking" stone, from light cape rough.
The Fancy Intense Yellow Pear Shape below has a totally different type of faceting on the pavilion ( bottom) of the stone.
If a cutter has darker cape rough, using the same method as the Fancy Intense would make sense. In this case, the cutter is aiming to increase the perceived color.
In contrast to that, the U-V cushion is cut just as that cutter would cut a D color.
The pear shape from a few posts above, for example, an M color- is cut using methods for colorless diamonds.
The cutter is probably trying to achieve a "white looking" stone, from light cape rough.
The Fancy Intense Yellow Pear Shape below has a totally different type of faceting on the pavilion ( bottom) of the stone.
If a cutter has darker cape rough, using the same method as the Fancy Intense would make sense. In this case, the cutter is aiming to increase the perceived color.
In contrast to that, the U-V cushion is cut just as that cutter would cut a D color.
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Another interesting aspect is how the advances in cutting techniques have allowed more yellow stones to come to market.
The advances I''m referring to are very different from the advances that have swept the RBC colorless cutting factories of the world.
I''m talking about "color retention" technology.
The radiant cut, developed by the late Henry Grossbard, was modified by many other cutters to work very well for magnifying the face up color of "cape" rough.
That means that diamonds that were cut to "off color" rounds, are now being cut to light yellow radiant cuts, and cushions.
Great point by Glitterata.
The stone below is a Y-Z color stone- graded EX cut grade by GIA- a rare animal indeed.
In my opinion, it was a lovely stone- but much less colorful ( yellow) as compared to a Y-Z well cut for color Radiant.
Part of this has to do with the design of a modern Round Brilliant- it minimizes perceived color.
The advances I''m referring to are very different from the advances that have swept the RBC colorless cutting factories of the world.
I''m talking about "color retention" technology.
The radiant cut, developed by the late Henry Grossbard, was modified by many other cutters to work very well for magnifying the face up color of "cape" rough.
That means that diamonds that were cut to "off color" rounds, are now being cut to light yellow radiant cuts, and cushions.
Great point by Glitterata.
The stone below is a Y-Z color stone- graded EX cut grade by GIA- a rare animal indeed.
In my opinion, it was a lovely stone- but much less colorful ( yellow) as compared to a Y-Z well cut for color Radiant.
Part of this has to do with the design of a modern Round Brilliant- it minimizes perceived color.
Jewelove
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A very interesting question indeed. The faint colors are certainly not fancy colors. There is an inherent difference in the crystal structure and the atoms present in the cape series and those in the fancy series. Mny people get confused in it, but the colors of fancy are close to colored gemstones rather than the cape series. For eg. Fine Ruby and Red diamond look pretty similar to the untrained eye.
We'd glad to answer any further queries.
We'd glad to answer any further queries.
Jewelove
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Jewelove,
Thanks. I'll look up the difference in lattices.
Is it appropriate then to talk about Fancy colours in gem terms (hue ...)?
One last question, I promise
. Why does fluorescence not affect the appearance of the lower coloured stones?
PS. I'd love to see a diamond of the same colour as a fine ruby.
Thanks. I'll look up the difference in lattices.
Is it appropriate then to talk about Fancy colours in gem terms (hue ...)?
One last question, I promise
. Why does fluorescence not affect the appearance of the lower coloured stones?PS. I'd love to see a diamond of the same colour as a fine ruby.
Amethyste
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Amethyste
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Hi Jewelove,
I think your info is NQR.
There need not be any atomic difference between stones.
I am told the diamond in the video link at the bottom of this page would have been a lowish color like M-P had it been cut to round.
http://www.octonus.com/oct/projects/movies.phtml
Anyone who is interested in GIA''s grading should read both the fancy yellow article they published a few years ago which does explain how they grade. This should be read in conjunction with their latest Gems & Gemology article in Fall 2008 (I think?) article on D-Z grading.
It might help some other experts here answer their own questions.
Finally I am aware that GIA does accept challenges based on evidence including specrtal analysis of rough prior to cutting and polishing to their fancy color grading calls.
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HI All,
Jewelove, Garry and I agree that your answer is not quite right.
Without speaking to the "atoms" I'd be interested to see these red diamonds looking like rubies.
The above quote could not be further from the truth.
We've seen Y-Z colored diamonds that were far more chameleon like than a stone GIA called a chameleon- due to fluoresence.
Put simply, flouresence has a HUGE impact on S-T- all the way down to Fancy Vivid yellow- and even impacts how GIA grades the color.
Garry- I belive we can easily see how GIA falls on this one by the use of the word "Fancy"
Where I feel these lables miss the point is that they could be seen as a disservice to people like Amithyste- who own these lighter colors.
I'll bet that people who see the A's stone never for second see anything other than a yellow diamond.
Is a stone GIA graded "Light Pink" a fancy colored diamond?
ChunkyCushionLover
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Uhhh man are my eyes seeing things or have I been reading too many magnetic resonance papers lately. NQR in the world of physics refers to a magentic property call Nuclear Quadrupole Resonance is that what you were referring to? Seeing as Carbon is not Quadrupolar and has no Quadrupole moment what are you really referring too? The nitrogen impurities would have a quadrupole moment but man would I laugh if you guys in the diamond world actually measured that. I would doubt that you would get a very strong signal for low concentrations of Nitrogen and the even lower concentration of the only spin active nuclei of Nitrogen which is 15N. I'm sure you will tell me what NQR really stands for in the diamond world
Edit: NQR= Not Quite Right (LOL I just answered my own question
Amethyste
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I am still not sure why my diamond didn''t earn the fancy grade, but hey, for me, it was an awesome deal and I would have paid SO MUCH more if it had a "fancy" wording on the cert. But I am curious to find out why it didnt "make the cut".
As for people assuming its a yellow diamond, let me tell you that the general public doesnt really know much about colored diamonds. I get the usual "Nice Topaz" or the "Huh? Yellow diamond? I thought diamonds are colorless, are you sure about that?"
I see a yellow diamond when I look at my ring, fancy rated or not - It IS yellow...
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HI A
If we were to hold a Fancy Light Yellow next to your pear shape, we would see a difference in color- the Fancy Light Yellow would have more yellow- a Fancy Yellow even more-so. GIA''s grading- in my experience- is fairly consistent.
The fluoresence is a slight wild card.
If a stone has Medium, or string fluorsence ( sorry for the spelling, I''m at a computer without spell check!) they may be slightly tougher on the grade. Therefore, your W-X may have a face up equivalent to a Y-Z...
Your stone is a perfect example of why the lables miss the point, if taken literally.
Your stone is a colored diamond, that''s indesputable. The only difference between yours and a Fancy Yellow is the degree of shade.
It''s true that the "public at large" is not really familiar with colored diamonds.
I am surprised you have not found the small percentage that is.
My wife wears a light pink diamond, and it''s rare that an observer will understand the signifigance of that.
But when they do, the reaction is usually pretty amazing.
Amethyste
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David -
Thank you for the wonderful reply and explanation - yes when I look at the fancy yellow pear you previously posted in this thread, I can see how different that one and mine look. My lemony really is not a bright and intense color, but you know what? its ok to me, I loooooooove the color of my pear, it is really the soft color of sunshine that I see when I look at it. Its all in the eye of the beholder.
do you have a picture of your wife''s ring David? I''d love to see it
PS: I''ll be in NYC around Xmas time, i''d love to arrange a meeting and finally meet
Thank you for the wonderful reply and explanation - yes when I look at the fancy yellow pear you previously posted in this thread, I can see how different that one and mine look. My lemony really is not a bright and intense color, but you know what? its ok to me, I loooooooove the color of my pear, it is really the soft color of sunshine that I see when I look at it.
Its all in the eye of the beholder.do you have a picture of your wife''s ring David? I''d love to see it
PS: I''ll be in NYC around Xmas time, i''d love to arrange a meeting and finally meet
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