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How are fancy yellow colored diamonds graded?

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Ercealan

Rough_Rock
Joined
May 5, 2015
Messages
34
Hi there. I have a fancy diamond. It isn't color coated, as it has not been able to scratch with a tungsten scriber. Under UV light, it shows a strong to very strong yellow fluorescence, not chalky, just plain yellow. I have looked to compare at jamesallen, but I look at their pictures, and it seems that some oval diamonds graded intense yellow, appear brownish yellow. The diamond I have, at around 7pm, indoors, seems kind of brownish yellow, but in daylight it seems intense yellow, very bright. Maybe it's because of the fluor. So my question, in what lighting does GIA grade fancies? Or if I were to buy a GIA graded fancy intense yellow, in what lighting will the diamond look fancy intense yellow? thanks
 
If it is a Fancy Yellow, it will never look like a Fancy Intense Yellow unless it is cupped in yellow gold because if it does (without additional design assistance), then it would not be graded as Fancy Yellow in the first place.

I am not sure why you are trying to scratch your diamond. There many treatments that require specialized skill and tools to detect such as irradiation and HPHT. It sounds like you purchased your diamond without a reputable lab report? If so, perhaps you might want to consider sending it to GIA instead of guessing and looking at online pictures?

Finding a yellow diamond with fluorescence is actually quite common. However, the illumination level is usually quite faint. Fluorescence is not taken into account when GIA determines the colour grades of the FCDs they are grading. Since your FCD has strong yellow fluoro, it is to be expected that the colour seems more saturated when under a UV source such as the sun.
 
Chrono, the diamond is a family stone. It was purchased without papers I don't know when. It was scratched with tugsten carbon scriber by me to rule out it being coated. It could not be scratched, so assuming no coating. I was not trying to scratch the diamond, just the coating if there was any, as the diamond would not be scratched being 10 on mohs scale, and the scriber less than 10, or am I mistaken?

My question really can be asked in another way maybe. If I were to buy a GIA fancy intense yellow, or a GIA fancy vivid yellow diamond, or any color, at what time of day will I see the color on the report? Indoors or outdoors? What kind of light source? The reason I mentioned JA is because they have real pictures, and it seems to me, that some of the fancy yellows even appear kind of brownish on their website. So, what light conditions does GIA try to replicate when grading fancies?

I could send it to GIA, but it would still not answer my question.
 
Fancy colored diamonds are chameleons.
They look different when you change the lighting, the environment or even your shirt.

That's why GIA grades them under specific lighting.
I'm sorry I do not know what that lighting is.

You can send your loose stone directly to GIA.
You don't have to involve or pay a jeweler to be involved.
Just look up their phone number in NY, NY or Carlsbad CA.
They also have locations in other countries.

I recommend you do not consider any other lab.
GIA is the absolute gold standard for fancy colored diamonds.
I'm not a gambler so I'd never consider buying one without a GIA report.

You set up an account with them and ship them your stone, or carry it in
They offer two colored diamond reports, one with more info than the other.
It takes weeks, but offer a rush service for, I think, twice the price.

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HI Ercealan,
My experience with Fancy Yellows is based on real world experience.
I am not positive on GIA's exact methodology, but its not the issue.
Basically the fancy yellow scale is incremental.
The grades themselves are fairly wide.
Put these two aspects together and you have a situation where the darkest stone graded Fancy Yellow will be more intense than the lightest stone graded Fancy Intense.
So there can indeed be times when a GIA graded Fancy Yellow looks like a fancy intense yellow.
Fluorescence does indeed play a role in grading.
Again, I can't speak for exactly how GIA arrives at te conclusions they do, but experience has shown me that they are more strict on diamonds of medium or strong fluorescence.
This plays out as follows: A Fancy Yellow with Med or strong fl may look more intense than an inert intense yellow
As I mentioned above, this can happen without fluorescence, but it's more common with fluorescence.

In terms of lighting used:
the commercial photography systems are designed to equalize and standardize lighting.
IMO this s not the best methodology when photographing Fancy Colored Diamonds.
Hypothetically speaking we should use the same light for all diamonds to equalize results.
In reality, the different types of light performance in different cuts- when added to the aspect of perceived color means that different stones react to light differently. This includes variations in intensity of light, color of light as well as the direction the light is coming from. Change any of these aspects and you get different results.
Fluorescence plays a HUGE role in changing thee look of a fancy yellow diamond based on lighting.
I'd imagine that your stone looks pretty yellow in sunlight, but it might not.

Without a doubt sending the stone to GIA will be in your interest if you want to know what you've got.

And please..... stop trying to scratch it:)
 
Ercealan,

I admit that I too am confused over what you’re trying to accomplish here.

The facts are easy enough though.

The GIA lab color grading environment for fancy colored diamonds is a white box called a Judge II viewing booth with a white plastic tray holding the stone. You can buy the box directly from the manufacturer and you can get the tray from GIA:

http://www.rpimaging.com/x-rite-judge-ii-s-viewing-booth.html?gclid=Cj0KEQjw4fCqBRDM1ZKhk5jfo6IBEiQAZQ97OK1oEE36b_GVMYIVlc4TRP8B-bBs5PliQ3zqL-SHn0EaAhJX8P8HAQ

They use the 6500k ‘daylight’ fluorescent bulbs from the same manufacturer.

GIA doesn't provide photos and it's unlikely that the JA photos are taken in this same lighting environment. The exact details of how they take their pictures is a trade secret and there are variables in the image other than the lighting. Those are secret too.

By the way, just for the benefit of other readers. Your scratch test is a really bad idea. Although it's true that diamond is harder than tungsten, it’s possible to chip the facet junctions doing this unless you’re extremely careful. Resistance to scratching and resistance to chipping are not the same things. It doesn't even answer your coating question unless you carefully did your scratch on every single surface.
 
Thank you denverappraiser, that is what I needed to know.

Yes, all surfaces were tested, it really doesn't seem like rocket science to me. I just wanted to find out if the diamond was completely worthless being color coated.

And I may or may not send it to be graded. I was thinking maybe a pre report with EGL first, and if it is worthwhile maybe a cert with GIA, depending on results. The diamond has one black inclusion, visible to the naked eye, so probably get an I1, but the color is nice, added to the strong yellow fluorescence.

Thank you all for the replies!
 
Again, I"m at a bit of a loss as to why go through this brain damage unless it's just for the entertainment of learning more about what you have (which is a fine reason by the way).

If you are planning on selling it, an EGL is a terrible substitute and they actually cost about the same (the version of report they call a pre-grade report doesn't include this). That intermediate step gains you next to nothing. If you're insuring it, you've got the same problem. An EGL doc undermines your coverage. Origin of color is a big deal. The difference between irradiation and natural is terribly important as is the exact color determination and the saturation.

If you're trying to come to some sort of value, for example what JA would charge for something similar, 100% of that pricing starts with those GIA grades.

On the other hand, if you already own it, aren't selling it, and aren't planning on insuring it, it doesn't make much difference either way.
 
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