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Back to the title of this thread. Recently I’ve had 2 friends (PSers so you know they’re discerning) who received AGS diamonds only to send them back because in their opinion the color grade was off by at least one if not two comparatively speaking to GIA. This was my experience as well but not as recently as theirs. Anyway just be aware and do your due diligence and you should be fine. Each stone (GIA or AGS or another lab) needs to be evaluated on their own merits. Labs-more specifically the people evaluating and grading the stones are human beings and therefore fallible.
But it seems as at least some of the time AGS is soft on color as compared to GIA.
Are they in the D-E-F range? Do you think GIA or AGS have any difference in grading those colors? Most I've seen complain about the color grading is is in the G-K colors. Just want to know if anyone has ever thought the colorless range is a bit off.
One of my friends got an AGS F and it was visibly tinted. In both our opinions.
I don’t want to paint with a broad brush but just sharing a few experiences. Each stone must be evaluated by one’s own eyes imo.
many people just repeat what they hear. that is how rumors get started.
I just bought a D color AGS graded that's why I'm a bit curious. I haven't received it yet. I hope I'm not part of the 1% that got a stone that is graded softly by AGS. *fingers-crossed*
Consumers should keep in mind that any lab hoping to take any business away from GIA cannot grade color and clarity more conservatively than GIA grades. To do so, would severely impact their chances of finding clients for their lab. They can hope to grade the same as GIA if they have the best motivations and they must compete with labs that grade a little bit softer than GIA at the same time.
The f range is very narrow either its an f or not.
Same with D and E
By comparison the I J K ranges are huge.
" 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.
Back to the title of this thread. Recently I’ve had 2 friends (PSers so you know they’re discerning) who received AGS diamonds only to send them back because in their opinion the color grade was off by at least one if not two comparatively speaking to GIA. This was my experience as well but not as recently as theirs. Anyway just be aware and do your due diligence and you should be fine. Each stone (GIA or AGS or another lab) needs to be evaluated on their own merits. Labs-more specifically the people evaluating and grading the stones are human beings and therefore fallible.
But it seems as at least some of the time AGS is soft on color as compared to GIA.
@missy This is a little concerning...ugh
Just more info to enable you to aim for your F
Yeah it is subjective and prone to human error.
I just bought a D color AGS graded that's why I'm a bit curious. I haven't received it yet. I hope I'm not part of the 1% that got a stone that is graded softly by AGS. *fingers-crossed*
The parent master sets are the same.Interestingly, this article from WF suggests GIA and AGS use the same master sets for colour determination,
A Guide to The AGS vs The GIA
An overview of the differences between The AGS vs The GIA diamond cut grades. Distinct systems that give significantly different results.www.whiteflash.com
Locations of Master Stones in the Grade Ranges.
Every individual grade designation on the D-to-Z scale is actually a range of colors within that grade. The GIA master stones are located at the highest boundary of each grade range (figure 9), that is, at that end of their respective grade range that has the least color. Therefore, a diamond with less color than the G master stone (but not less than the F) would receive a grade of F. If the diamond appears to have the same amount of color as the G master, it would receive a grade of G. When a diamond has
come to the same color grading results. Within a given set (up to about one carat), master stones should not vary more than 10 points from one another. There can be no eye-visible inclusions, and they cannot exhibit “off-colors” such as having a subtle brown or gray cast.
Fluorescence is also an important consideration. For the E-to-J range, GIA only accepts diamonds as masters that have no observable (reported as “none”) fluorescence. For K and lower, a “faint” fluorescence reaction is acceptable. While a more strongly fluores- cent diamond might be used as a master if strict labo- ratory conditions were always to be used (i.e., stan- dardized methodology, lighting, and environment), GIA has no way of determining whether client master stones will be used in these conditions. With regard to the acceptance of faint fluorescence for masters K and lower, our experience has shown that, as the amount of color increases, the impact of faint fluorescence on color appearance is less noticeable. Also, we have found that diamonds in the lower color grades com- monly fluoresce, so it would be difficult to locate stones with no fluorescence in this color range.
A diamond selected as a master stone is not neces- sarily an exact duplicate of the GIA master of the same color grade designation. A diamond is an accept- able master when it falls in the range of repeatable visual tolerance as established by the laboratory over the years. Consequently, a diamond may be acceptable as a master if it is very close to the GIA master, but is very slightly to the higher or lower side. Our research has shown that skilled graders reach a point of visual tolerance (i.e., the range of repeatability) for D-to-Z color discrimination at slightly less than one-fifth of a grade at best. While this fraction may appear large, it is important to remember that even between whole grades the differences are extremely subtle. For exam- ple, it is common for untrained observers to see no dif-
slightly more color than the G master stone but less than the H master stone, it will be called a G color. Any diamond, no matter how colorless in appear- ance, receives a D grade if it appears to have less color than the E master stone. Thus, no D master stone is necessary.
Instead of trying to match the color of a diamond with a reference color, the GIA system involves placing or bracketing the color between pairs of master stones, which for most observers is an easier task. In general, the grading process is one of pro- gressively narrowing the range until the diamond fits within a single grade (i.e., more color than the master stone on the left, and less color than the master stone on the right).
After the diamond to be graded has been wiped clean with a lint-free cloth, it is initially placed at one end (far left—the colorless end—by laboratory convention) of the tray on which the master stones are set in the viewing box. Using a pair of rubber- tipped tweezers, the grader moves the diamond along the set of master stones until it appears to be
one to two grades past the estimated color grade. It will, at this location, appear to have noticeably less color than the master stone to its left. The grader then moves the diamond back by placing it consis- tently to the right side of each master for compari- son. When the diamond being graded appears to have less or the same amount of color as one master stone, and more color than the next master stone to its left, it has arrived at a single color grade range. Its grade is associated with the least colored of the two diamonds, since each master stone represents the highest (least colored) boundary marker in the range.
Some color grades in the D-to-Z scale may not appear to be different at first glance (for example, D, E, and F diamonds all appear virtually colorless). Therefore, it can be challenging for a grader to clear- ly place the diamond being graded between two master stones through the bracketing process (it may be located much closer to one of the masters). In this situation, it is common to identify the closest mas- ter stone, and then determine to which side of that master the diamond being graded should be placed.
Additional Considerations for Color Grading. Color Grading Diamonds that Differ Significantly in Size from the Master Stones. Overcoming the visual effect of size differences between the diamond being graded and the master stone is an additional chal- lenge even for the most experienced grader.
And though we are discussing higher color ranges here this is interesting.
Color Grading at the Lower End of the D-to-Z Range. Color grading at the lower end of the scale (below N or O) can present special challenges for graders. As the color becomes more noticeable, so do the differences between color attributes. In deter- mining the relationship of a diamond to a master stone, an observer must contend with subtle differ- ences in tone (lightness or darkness) and hue (as opposed to the predominance of saturation in the decision making for other areas of the scale).
The difficulty in making grade distinctions between single color grades in this range limits the usefulness of all the individual color grades in the O-to-Z range.
Interestingly, this article from WF suggests GIA and AGS use the same master sets for colour determination,
A Guide to The AGS vs The GIA
An overview of the differences between The AGS vs The GIA diamond cut grades. Distinct systems that give significantly different results.www.whiteflash.com
The thing to keep in mind is that assembling authorized master sets is done according to same strict GIA criteria, whether for their own labs (GIA has dozens of masters in use across their many locations), or for other labs such as AGSL. Accuracy and consistency is actually more of a challenge for a network of labs using a large number of different sets, rather than a single lab using a few. Whatever small variances might be introduced in the process of vetting master sets would likely impact a large network more than a smaller one.
This is a regular topic of conversation on pricescope and in all my years here I have never seen any statistically significant evidence sited to demonstrate that one lab is “softer” on either color or clarity than the other. There is only anecdotal evidence of a stone here or there that show grading variance. And that variance almost always falls into the understood and acknowledged (by all labs) tolerance of a one grade differential.
We deal in both AGS and GIA graded diamonds and have extensive experience with both labs. We have never seen any evidence of consistent grading differences. Every dealer has occasion to question a color or clarity grade at the lab from time to time, and re-checks are a very common process in both labs (and a revenue center because they charge for it!). And once in a while a borderline grade is changed by the process of escalating to a more senior grader. This is just more support for that one grade tolerance inherent in human grading.
Automated color grading is now being done by GIA on a subset of diamonds submitted to their labs. Eventually it may be possible to do all color grading by machine, which would eliminate the human factor. But then there will still be instrumentation deviation to consider!
The vast majority of diamonds we submitted to AGS for secondary grading received the same color and clarity grades as their first grading. When AGS differed from IGI or GCAL, the results were only off by one (E vs F color, VS1 vs VS2). More often than not, AGS was looser/easier on the diamonds than IGI/GCAL!
Automated color grading is now being done by GIA on a subset of diamonds submitted to their labs. Eventually it may be possible to do all color grading by machine, which would eliminate the human factor. But then there will still be instrumentation deviation to consider!
Yeah it is subjective and prone to human error.
I just bought a D color AGS graded that's why I'm a bit curious. I haven't received it yet. I hope I'm not part of the 1% that got a stone that is graded softly by AGS. *fingers-crossed*
im sorry the facts must be re-presented, each time there is this "chatter" about agsl being "softer" on color than gia. and to patiently do so, time and time again is quite the feat. especially, when zero, first hand documented evidence, is even bothered, to be presented to validate and substantiate such "chatter". ive found when the chatter is repeated enough, without correction, it becomes rumor, negatively affecting both consumer and vendor/business. newer members seem to be the most susceptible and fall prey to those ongoing rumors.
as an example, a new member asked about her d color whiteflash aca diamond. she was concerned with ags being "softer" and conerned. because i have recent, first hand experience with a dual certed diamond that is f color, along with the cross validating lab reports, i decided to share my experience... well, that was enough to set off the "chatter"... (and because i am a newer member, the "gang ridicule")
in my personal first hand experience i find that agsl and gia grade comparatively.
another member's agsl and gia experience with yet another set of documents, featuring cross validating color grade of h color
AGS and GIA laser inscription
Hello all, we bought a Canera H&A diamond and are having it set. I was looking at the AGS report today and noticed there was also a GIA number on there. I pulled up the GIA report and there are some slight discrepancies in the measurements. Could the two laser inscriptions be due to the diamond...www.pricescope.com
Ha! All the regular posters here are well acquainted with the need for repetition! (AMIRITE y'all?)
It's all part of the education that is provided here. As the saying goes "repetition is the Mother of learning".
First, there are new people coming here all the time with the same questions and who have heard bits and pieces of that chatter that they seek to have confirmed or refuted.
Second, there are a number of myths that get perpetuated down through the years. Part originating from simple lack of knowledge and part from industry members with particular agendas.
I am sure this happens in every industry. It's important to just have patience and do your best to provide the most objective understanding of the issues possible. Then let folks make of it what they will.
As you allude to in your own case and the other thread you reference, if we were to have a competition of individual examples of grading variance between GIA and AGS, the number of examples in agreement would swamp the exceptions. But it is human nature to focus on the outliers. The variances make news while the agreements are taken for granted.