So... does that mean if we go to, let's say for example, Holland, diamonds will look better than they do in the US?

Of course I'm joking, but I'm a little confused about this comment. Care to extrapolate?

Wow fascinating. So you mean two different gemologists might give the same diamond a different color grade?

Just thinking out loud...

If a loose diamond is typically graded face down, once it is set could it receive a different color grade?

(Assuming set stones are graded face up)

Let's move on to discussing fancy colors, and their grading
To help conceptualize GIA color grades, I'll use a ruler to describe the grades' calibration.
At the left end of the ruler is D. Totally colorless.
E color starts at .01 inch. There's almost no difference between D and E, it really takes a sensitive eye, in optimal conditions, to be able to see the difference.
F starts about .02inches after E. G starts at about .5 inch.
The sum difference between between the "highest" D, and the "lowest" F  is about .5 inches.
Seeing the difference between an F and a D is not all that easy either.
Now we're at G color, which is about 1/2 inch wide. Meaning that the difference between D-F is the same as between G-H.
I color is 3/4 inch. J is about an inch wide.
The difference between a J that almost made I color, and one that just missed being downgraded to a K is fairly easy to see.
That's one reason some J color stones look whiter than others.

Let's keep moving down the scale. All the way down to Fancy Yellow, Fancy Intense Yellow and Fancy Vivid Yellow.
Let's go back to our ruler......we now need a yardstick.
Fancy Light Yellow is about a foot wide. Fancy intense is, as we shall see, about 18 inches on this same theoretical measuring scale.


Incredibly enough, both smaller stones were graded Fancy Intense Yellow by GIA- the stone on the far left ( R3454) is graded Fancy Yellow
I can see the middle stone as Fancy Intense, but the stone on the far right is arguably a vivid. No question it's as dark as an Intense can be.
I have had the opportunity to evaluate two stones , where one was lucky, the other not at all- meaning the Intense yellow was actually darker than another stone graded Vivid Yellow by GIA.
Since grading is done by humans, there's going to be areas of overlap that produce some results that are less than consistent.
Having pointed out the shortcomings, I'd like to add that the system is very good- and works well in the real world.
There are machines which can - arguably- grade the color of diamonds.
But this is an area I don't think will ever be effectively mechanized.

Unless I have stones loose and side-by-side, I cannot tell the difference between D to I.  At the end of I and the start of J, I can just barely detect some of the yellow that mixes in to them.  On the fancy side, I have a very hard time telling the difference between the Y-Z range up to the start of the fancy yellow range.  Again, I just do not have the visual acuity to tell the difference.  The photo above is what I requested from David to help make the decision between those three stones.  [We chose R3467].  We had originally been contemplating the differences in preference between R3454 and R3469 and were having a hard time deciding, but then R3467 showed up on the site.  Wowzers!

I can certainly see what you mean by the measurements corresponding to the ruler measurements, very interesting.  Those blurry areas between the lines probably give DBL customers some tremendous values--I know it did for us!

You're so welcome guys- thank YOU!
When we're talking about color grading, it is a good time to remind readers that GIA grades Colorless , and near colorless in the "face down" position

Fancy Colors are graded "face up"- which really does seem more pragmatic, if you think about it.
It's less consistent though.
Think about the methodology and you can see why.
In the photo above there's a very consistent background ( the super white diamond grading paper)
Plus, diamonds are more stable when placed on the table. Even if you ewanted to compare diamonds in a diamond color grading tray, they are not as easy to compare face up.
But GIA also looks at stones under a lamp, face up. Using tweezers.

Thanks for this explanation, D.  I thought the range for FLY would be greater than FIY and Vivid would be even less.  Interesting.

It's clear that 4.13ct tw pair is darker than the K color.
Let's compare them to the M color directly.
This photo, taken from the traditional table down color grading position shows that the center stone is slightly darker than the stones flanking it.

I love that last comparison.  It's neat to see how a RB can hide color quicker than  a fancy cut.  Though if you are looking for warmth, fancy cuts are awesome!

Just thinking... fancy colors are graded face up, correct?  If so how does that affect a FIY RB vs a radiant.  As in if they look about the same from the top does it mean from the side they look totally different?

I hope I asked that well enough to understand LOL