clarity graded with backlighting??

[rkp2be]

FF and I are currently looking at a "VS2" RB. The cert shows only one small-medium sized cluster of inclusions in the girdle area (by cluster, I mean that it almost looks like one big inclusion, but it''s actually more than one that are touching). No "additional clouds or pinpoints" are noted. I brought it home with the cert to check it out with my ideal-scope... and lo and behold, we become convinced that it is a different diamond and/or has the WRONG cert, as the inclusions we are seeing in the ideal-scope look completely different (and more numerous!) than the ones on the cert! The IS shows 11 inclusions (FF counted) in a more broad pattern, all clustered in one area of the girdle (so in same location as the cert shows, just in a larger/different pattern). Now we can also see one inclusion in the table area, off to the side.

Long story short: we''re told that clarity is graded without backlighting - that the IS produces a different picture of the inclusions, as the backlighting causes them to reflect in a different way. IS THIS TRUE??? I''m so confused - I''m positive I recognize the stone from when I looked at it through IS before, and it JUST got back from being certified 3/28/08 (EGL USA) - furthermore, everything else on the cert matches what I was told before (#''s etc.) so it doesn''t seem like they accidentally shipped the wrong cert w/ the diamond...

TIA for any insight on this!

 

[The Mole]

If a certain inclusion is a "reflector" meaning because of it''s position in the diamond it is reflected into other facets, grading laboratories will only plot the original inclusion and not the reflections. The reflections are considered in the final clarity grade of the diamond however.


I''m not saying that it is true in your case, however it is a possibility.

 

[DiamondExpert]

Mole has a good point - the IS is NOT an instrument designed for use as a clarity grading tool!

...and clarity gradging is not done with backlighting, but with darkfield (oblique angle) lighting and reflected light.

 

[rkp2be]

thanks for the feedback! yes, i realize the IS isn''t for clarity grading

but seeing all those "extra" inclusions in a "different" pattern scared us... i really just wanted to confirm that clarity grading is not done w/ a backlight.

the one thing that made me question the jeweler when he told us this, was that after locating the seemingly "extra" inclusion in the table area, we could see it with our naked eyes. Obviously it''s an actual inclusion (not a reflection due to backlighting) if we can see it that way, but it seems to be more toward the center of the diamond than the inclusion on the plot (i''d have to look again to confirm this). i know not ALL VS2''s are completely eye clean, and by the definition of "normal viewing distance in certain lighting" i suppose this one probably is, as I had to really scrutinize the diamond to see it, and i could only see it when a certain facet became white - but when it did, you could CLEARLY see the little black dot.... anyway, jeweler is taking it back to take a it again and will let us know what to make of that.

 

[niceice]

Diamond clarity is determined without backlighting? Huh? Oh man, I''ve been doing it wrong all of these years! Who knew? I''ll bet this would be useful information for the people who design the Gem Scopes - they could eliminate that whole pesky backlight set up! Maybe I can ditch the fiberlite too, who needs to illiminate the diamond from the side anyway? Oh heck, let''s live on the edge and get rid of the overhead light option too! It''s always in the way anyhow! From now on, I''m going to grade in the dark! Oh wait, I already do that... Which is why I need the option of being able to backlight the diamond so that the inclusions might actually be visible... Hmmm, now I''m simply perplexed. What ever shall I do?

You might want to consult the expertise of an independent Gemologist, there is a list of appraisers available via the Resources / Appraisers link available at the top of this page in the PS menu bar. I''m guessing that somebody forgot to indicate an inclusion on the plotting diagram of the lab report - it happens. You are looking at an original lab report, right? Not a copy? Inclusions magically vanish off of faxed copies of lab reports all the time, it''s a mystery. That said, there have been several occasions where I''ve been evaluating a diamond and run across an inclusion or two which is not indicated on the plotting diagram on the lab report, I call the lab to inquire as to whether it is something that they noticed during their evaluation of the diamond and more often than not, it''s simply a matter of the person in charge of putting pen to paper during the creation of the lab report simply had a human moment and forgot to plot an inclusion. Unless the inclusion located on the girdle edge of the diamond is substantial, it would be a bit odd for the diamond to only be a VS-2. Perhaps you can post a copy of the plotting diagram from the lab report within your post?

 

[denverappraiser]

Since you just paid EGL-USA to plot it, they seem like the obvious choice for where to address questions about the plotting. Their contact information is on the report.

The purpose of the plotting diagram is to map details that are useful in identifying the stone and to indicate what was considered in setting the clarity grade. It’s not intended to be a drawing of everything in the stone. There’s a curious pressure on graders when it comes to plotting. As everyone who has ever attended a public school in the US knows, red marks on your paper are BAD. Diamonds with a lot of ink on the paper don’t sell as well as the same stone would if they used less ink. This flies in the face of the original intention of the plotting which is simply a matter of reporting the facts. If the good folks at GIA had been thinking in a marketing sense when they came up with this they would have used some other color for this reason but it is what it is and we’re locked into the color scheme now. For plotters who are fundamentally producing a sales document (meaning they are working on behalf of a seller), the way to mitigate this is to use the thinnest red line possible, the lowest saturation ink that could still be called ‘red’ and plot as few items as they can within their own methodology.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Jewelry Appraisals in Denver

 

[oldminer]

Labs nearly never draw the clarity plot identically to the actual inclusions. Clarity plots are nearly all seller friendly documents with lightly drawn "representations" of the clarity situation. I used to have an employee who drew what he saw and filled it all in. No one would accept his plots done that way although technically correct. If an actual diamond was that eye-visibly problematic, then his plots would have been acceptable, but nearly all clarity marks are invisible and ought to be entitled to being lightly represented on paper.

The business of operating a lab is like walking a tightrope between what sellers want and what consumers need. Consumers may want everything, but many of them really want to know enough to make a decision and not ''everything". Others want it all and that''s okay, too. If you hae a diamond with a heavy handed clarity plot your insurance carrier might argue that you take a lower clarity diamond than what you actually had because your plot makes the stone you lost look quite imperfect. If the clarity grade given to the diamond on the insurance report and the clarity plot don''t match, it is logical to understand a problem of communication may arise and only after the diamond can''t be re-examined.

 

[LegacyGirl]

Date: 4/2/2008 12:01:37 PM
Author: niceice
Diamond clarity is determined without backlighting? Huh? Oh man, I''ve been doing it wrong all of these years! Who knew? I''ll bet this would be useful information for the people who design the Gem Scopes - they could eliminate that whole pesky backlight set up! Maybe I can ditch the fiberlite too, who needs to illiminate the diamond from the side anyway? Oh heck, let''s live on the edge and get rid of the overhead light option too! It''s always in the way anyhow! From now on, I''m going to grade in the dark! Oh wait, I already do that... Which is why I need the option of being able to backlight the diamond so that the inclusions might actually be visible... Hmmm, now I''m simply perplexed. What ever shall I do?

Better yet why don''t you just turn all the lights off and grade them in the dark!

 

[rkp2be]

yes, it''s definitely the original cert we''re looking at. i could try to get a picture of the plot when we get it again today/tomorrow. now FF is saying he thinks what we see face up w/ the naked eye is from the cluster of inclusions in the "girdle" area.... he remembers the plot showing the inclusion being in the table, i remember it being more off to the side - especially since the eye-visible table inclusion is not on the same side of the diamond as the grouping of inclusions seen in the girdle area w/ the IS. that probably doesn''t make sense.

As far as the VS2 grade w/ what the cert shows, the jeweler said that it''s a borderline VS1/VS2 (so a really clean VS2).

i looked in PS''s list of appraisers but there aren''t any in my area (charlotte, nc). i could see if the jeweler would ship it to one of them for us. and the jeweler will definitely contact EGL-USA if it does in fact appear that they''ve left something out (who knows.... it was graded on a friday, maybe the grader was looking too forward to the weekend!).

...so grading is done with backlighting? by this you mean backlighting is used to help tell what inclusions could be reflected in various light sources, but the actual plotting is only done using the type of lighting DiamondExpert mentioned?

wow, i''m probably thinking about this way too much.

thanks again for all the feedback, i''m learning tons!

 

[DiamondExpert]

By backlighting I thought you meant with the ''scope diaphram open, which it wouldn''t be with darkfield lighting where the light comes in from the sides and oblique angles from the back, but not directly from the back. Of course, there is no LAW restricting the use of any type/angle of lighting for clarity grading, but certain procedures are followed to keep things consistent...and it''s also just easier to see inclusions with darkfield lighting.

Sorry for any confusion

!

 

[niceice]

Date: 4/2/2008 2:00:14 PM
Author: rkp2be
...so grading is done with backlighting? by this you mean backlighting is used to help tell what inclusions could be reflected in various light sources, but the actual plotting is only done using the type of lighting DiamondExpert mentioned?

Yes and No... Gary is technically correct, but he''s thinking like a Gemologist and you''re thinking like a consumer - so I addressed the question from the perspective of a consumer who would see the lighting used as "back light" because light is seen as coming from behind (in back of) the stone to provide illumination of the inclusions... You are back lighting the stone when you look at it through the Ideal Scope, but doing so with a much more direct light source than is found on a Gem Scope.

 

[rkp2be]

ahhh that makes more sense! i got the stone/cert back - FF was right, the inclusion is off to the side of the table (not in the girdle), so i guess it makes sense that i''d be able to see it w/ the naked eye if i''m really studying the stone. tonight i looked at the stone in every type of lighting possible inside/outside, studying it''s performance (i got real close but wasn''t trying to see the inclusion) and i never saw it.

also, the jeweler looked at the stone again, and he backs up the cert. so do you think the stone got the VS2 grade for such a small inclusion (on paper) because the inclusions are reflected around more?

in your professional opinions, would you consider this a red flag? everything else about the stone seems awesome (IS image etc.) - the only thing i''m concerned about is the relatively low crown angle (33.2)... but i might start a different thread for opinions on the stone overall...

thanks again for your input!