Silly diamond color and grading questions

[kmoro]

I’ve been reading about color grades and have learned that there is a slight range in each color. For example, a “low” F would be closer to G than E .... which leads me to my question: is there a range in D color? It seems to me that would be either totally “white” or not, and therefore also would have little variation in grades by GIA vs AGS. Some people say that AGS color grades are about .5 grade higher than as same stones graded by GIA. Is it possible either AGS or GIA would give color grade D to a stone that had the smallest tinge of color?

And a question about grading: is it true that diamonds will be examined by more than one person before final grading in reputable labs like AGS and GIA? As some aspects are subjective, it would be reassuring to know that grading is “double-checked.”

Thanks again to all the knowledgeable types!

 

[rockysalamander]

Every color band has a range, and that range is wider the lower you get. However, your ability to see color is biologically determined (color sensitivity). In my experience, most people can start to see color (absent a comparison) at I or J. If you want it to look "pure white" to every single person, stick with F and above. I can see all the ranges of color and can typically grade to GIA standards, but I just don't mind color. I have a lot of antique stones that range from E and down to S. So, figure out what colors you like and can actually see. My daily diamonds are G, H, and L. Even under close inspection, it is a rare person that can see any difference between the G and H. Many can't even see the L vs. H. Human eyes are incredibly variable in color (and light) detection.

GIA is generally a slight bit more strict on color than AGS, but I'd say only at the margins. When you have a stone that it between the color set ranges. A D-color will look white in either system. So will an F (and even a G to most).

GIA grades diamonds against a standard set of diamonds. A human uses their eyes to grade against that standard. I assume that there are multiple checks along the path. @Rockdiamond @Wink @Winks_Elf @Rhino are more familiar than I with AGS and how they grade color within their lab.

One other note is that diamonds have one of three body colors: yellow, brown or grey. That body color can influence the look of the diamond and detection of color. I happen to prefer brown and grey over yellow, but that's personal preference. In high colors (G and above) the body color is pretty meaningless. But, it becomes more important as you move down the color band.

All of the color talk is meaningless if the diamond is not well-cut. A well-cut diamond will mask more color than an average or even poorly cut stone. Also, color is most detectable from a 45-degree tilt and down to the side-view. From the top, most find M colors can look white.

 

[sledge]

Great post by @rockysalamander!

From research I've done, it's my understanding that AGS utilizes a master set of stones identical to GIA.

Also I've read some information about the light bulbs used for testing is just as critical. In fact one article (I believe here on PS) it mentioned how some bulbs may put out small amounts of UV and in stones that have fluor, it could activate the fluor which could ever so slightly alter the stones appearance.

While I think grading color in an honest, repeatable and most objective manner possible is the intent it is a bit perplexing to me there are no formal diamond test methods. In other materials it's very common to test various characteristics using ASTM methodologies that clearly define the test procedure, equipment, etc so that if you test tensile strength for instance it is (theoretically) the same regardless which lab it comes from assuming the lab is accredited and using the exact same test methods.

That said, color is a thing that will always be subjective so you could get some variation in test results/grading. But because of the human nature involved it seems more of an argument to standardize all the other elements, including vision and color sensitivity of test graders.

 

[sledge]

Giving proof of what @rockysalamander was talking about with how color can be perceived at various angles, undertones, it's whiter with a well cut stone, etc I'd like to share the following.

The stone in question belongs to @lovedogs and is a 1.04ct N VS1 from HPD/CBI. I find myself fairly color sensitive and took particular interest in this stone as (for me) it broke barriers of color I'd never dip below.

and glam shots are here!

Pictures are here and it's shipping in the next few days!!!!!!

It's arrived!!!!!!! I'll start a new SMTB thread later today when I have time, but wanted to update with pics. This is seriously beyond my wildest dreams. It's the perfect color for me....super white in some lights, and in others it honestly looks champagne. I am in love, and can't thank @Wink @Winks_Elf Paul Sledgers, Jamie, and everyone else at HPD enough. No wonder anyone who has seen a CBI can't go back. It's just beyond anything I've ever seen. Now to pics!!!!


Inside, no real lighting.
Outside, in the sun/dappled shade:


On my maltese's white fur haha:


And my personal favorite, looking like a champagne diamond in the shade under the covered patio


Whoops, too many pics. More champagne pics in the next post!

Champagne pics:



And one more less champagne tone, still in shade.


Seriously, everyone should see a CBI if they can. It's mind blowing.

 

[RetroQT]

@sledge Great example! I just recently purchased an O/P stone set in rose gold (avatar) and it is just one color grade lower than @lovedogs beautiful example of an N. My stone has the brown undertones and it shows a lot of color. I believe the rose gold bezel influences that as well as the cut (Crown Jubilee). I think @rockysalamander gave wonderfully detailed information of this as well.

 

[oldminer]

" it's my understanding that AGS utilizes a master set of stones identical to GIA. "
This reveals the problem, since every early official master set was graded by human eyes in comparison to the GIA Mother set. Now, there are many sets which have been created in comparison with other random, but well controlled GIA master sets. The eyes are not the very best color discriminators for the fine gradations found in diamonds. You will find inconsistencies in master sets if you look at many of them and I have. My findings are not alone, but in agreement with several other long time gemologists who have seen quite a range of colors assigned as master diamonds. It is a bit like telling a secret to one person and having the secret retold down the line to the tenth person in line just to laugh at the strange way our perception and senses may alter transmission of data.

No doubt the Mother set at AGS is highly similar to GIA's Mother set. However, no regular lab employee uses either Mother set for grading other diamonds. The sets used are one or more generations away from the original Mother set and contain nuanced differences. The labs may use very slight different levels of tolerance to set the change point from one color to the next and this does create differences in outcome.

D color has an extremely very narrow range of possible color tint, but there is some range within even at this top color. Even if your eyes or my own can't see it, the range is there and may sometimes have some tiny meaning in the overall scheme of diamond grading.