Understanding Inclusions on GIA Plot Diagram

[Defender]

I have learned that an "eyeclean" Emerald with an SI1 clarity is a pretty hard thing to find, but I am willing to compromise a little if the inclusions are not immediately obvious.

With this in mind, I was looking at this particular Emerald which is an SI1. I have noted that most of the inclusions appear to be located in corners and are outside of the table. However, some of these marks and notations on the GIA plot look a bit scary to me. I have see a note of a cavity, but I am unsure of which of the marks on the plot map refer to this inclusion.

So, I am posting this little plot map from the GIA certificate for the experts to comment on.

I am curious if this stone looks like a loser, or whether it is worth a look? It also might serve to better help me to understand these plot maps and notiations on the GIA certs

 

[valeria101]

Date: 4/12/2006 6:30:42 PM
Author:Defender

I have learned that an 'eyeclean' Emerald with an SI1 clarity is a pretty hard thing to find, but I am willing to compromise a little if the inclusions are not immediately obvious.

... then, this looks like a potential winner to me.

. I have see a note of a cavity, but I am unsure of which of the marks on the plot map refer to this inclusion.

... guessing a bit (it should be green, but the picture doesn't show color much), the thing on the pavilion picture on the top-left corner. Not scary - unless the girdle gets too thin there, which would be noted by the girdle width on the cert. Is it?
Could be another...


I am curious if this stone looks like a loser,

no

or whether it is worth a look?

yes (IMO).

I wonder what is the bug on the lower half of the right-side of the pavilion. Stuff sometimes reflects inside emerald cuts if places along the long facets - but I can't possibly guess if whatever that is might do that - it also takes a 'lucky' distance from the facets, etc. Whatever happens around the corners has the least chances to show, IMO.

If you are considering other such options, clouds, twinning and long feathers are 'nice' inclusions on EC (IMO) - the plot gets all-red and scary with them, but the things are subtle in nature. Allot more so than crystals, for example. The most startling 'eye clean' SI2 emerald cut I ever came across had large feather under the crown facets and not much else (can't remember and never seen anything at 3X). GIA report showed this BIG red line crossing the entire pavilion - not flattering. Sure enough, I don't have as many examples 'on record' as a pro. If you get a seller to sympathise with your quest for an eye clean EC, they should be able to help way better than this

 

[Defender]

Thanks Valeria, that is really interesting feedback. The many large marks and notations on the plot and the mention of a cavity seemed very ominous to me.

Here are stats from Certificate:

Carat weight: 3.05

Cut: Very Good

Color: I

Clarity: SI1

Depth %: 66.6%

Table %: 66%

Symmetry: Good

Polish: Excellent

Girdle: Thick to very thick

Culet: None

Fluorescence: None

Measurements: 8.55x7.90x5.26 mm


By the way, this is an Emerald that is almost square at 1.08 ratio...

I was told that anything under 1.05 is called a Square Emerald byt GIA, and "gets marketed" as an Asscher these days. So, it seems that this rock may look more like an Asscher than an Emerald...Am I correct about this??

 

[valeria101]

Asschers are.. square emerald cuts. No difference... only fancy names; you are right about that. There is a certain look that goes with the Asscher name more often than not: (small table, closer to octagon than square because of deep clipped corners) - but there is no consistency in this, depends on where you are buying. How square step cut diamonds should look like it is a matter of taste - up to you basically. Brilliance does not depend on those characteristics.


I hope that one is a good copy of the lab report and no additional markings 'disappeared' from the picture. IMO, as shown it is a lucky Si1 and the clarity plot is definitely not crowded.


As much as I can tell.

 

[Defender]

The interesting thing is that this is a Blue Nile stone, and I just called them to get more info on it.

The consultant had not seen the stone but warned me that she tries to avoid any SI stone where the certificate mentions a cavity. This sounds like it is painting the picture with a very broad brush, huh?

With Blue Nile it really involves a leap of faith to buy the stone and have it shipped when they are trying to discourage you!

 

[valeria101]

Date: 4/12/2006 7:13:05 PM
Author: Defender


The consultant had not seen the stone but warned me that she tries to avoid any SI stone where the certificate mentions a cavity. This sounds like it is painting the picture with a very broad brush, huh?

Yes... almost every shop will tell you this. Unless they have a clean-looking SI step cut to show you - which does happen sometimes

With Blue Nile it really involves a leap of faith to buy the stone and have it shipped when they are trying to discourage you!

Too bad ... about the discouragement. If it is not too late, I wonder if a different seller can''t call this one in. Even if it is not listed under their name here or on their website. I remember someone else did this with a Blue Nile virtual listing

Anyway, hope their return policy is ''no questions asked''.

 

[Capitol Bill]

Date: 4/12/2006 6:30:42 PM
Author:Defender
I have learned that an ''eyeclean'' Emerald with an SI1 clarity is a pretty hard thing to find, but I am willing to compromise a little if the inclusions are not immediately obvious.


With this in mind, I was looking at this particular Emerald which is an SI1. I have noted that most of the inclusions appear to be located in corners and are outside of the table. However, some of these marks and notations on the GIA plot look a bit scary to me. I have see a note of a cavity, but I am unsure of which of the marks on the plot map refer to this inclusion.


So, I am posting this little plot map from the GIA certificate for the experts to comment on.


I am curious if this stone looks like a loser, or whether it is worth a look? It also might serve to better help me to understand these plot maps and notiations on the GIA certs

You are correct that an "eye clean" SI1 emerald cut is relatively difficult to locate (especially in the size you are considering). The plot you included in your post surely has potential to be eye-clean-ish. In this case I wouldn''t let the listing of a cavity distract you. It appears the cavity is not the main grader here. I would be more concerned with the feather(s).

The only way to know for sure is to order the stone and see for yourself. Blanket statements like "avoid any SI1 stone were the certificate mentions a cavity" make no sense because the presence of a cavity is often inconsequential.

Best of luck!
Bill Scherlag

 

[oldminer]

Clarity plots on GIA and other major lab reports are not directly repeatable. GIA will tell you their plot characterizes the clarity setting inclusions, but may not show all the inclusions. WHile that is a superb excuse for missing something, it is also important to understand that the quality of the clarity plotting is something that you cannot put total faith into.

The lower the clarity grade, the more variation would occur in repeated plots of the same diamond. It follows that plots of similar clarity grade diamonds vary a lot. There are some great diamonds with "cavities" as ther are some that really suffer from them. Where is the cavity? How visible is it? Is it invisible? Might it contribute to weakness or damage? Those are the issues. As you have been told, a blanket statement is plain wrong to rely upon.

It seems logical that the lower the clarity of a diamond, the more it needs you to personally see it. We can describe the color and cut pretty well, but the description of clarity faults as clarity gets lower becomes more and more challenging. There is more room for misunderstandings to occur.

The existing clarity plot looks promising. I would not be much concerned about a general avoidance of all stones with a cavity comment. The cavity could be in a very good place.

 

[niceice]

Date: 4/12/2006 6:30:42 PM
Author:Defender
(1) but I am willing to compromise a little if the inclusions are not immediately obvious (2) some of these marks and notations on the GIA plot look a bit scary to me.

Okay, by "compromise" I assume that you are referring to being willing to accept inclusions which may be more visible through a loupe or which are more extensive than those within a higher clarity... But are you willing to potentially "compromise" on the durability of the diamond? Probably not... Here is a trick to "reading" the plotting diagrams on lab reports:

I edited the plotting diagram to make it easier to identify which inclusions are actually the same as indicated on opposite sides of the plotting diagram. Imagine that there is a line between the upper and lower halves of the diamond, if you fold the lower half of the plotting diagram under the upper half along the black line that I added between the two diamonds you would have an accurate representation of the alignment... Looking at the top, the yellow arrows indicate the upper and lower halves of a feather (crack) running through the stone... The light green arrows located towards the bottom also represent a feather that runs through both halves of the stone... The pink arrow located in the nine o''clock region of the lower plotting diagram indicates another feather which would be a concern to me as a diamond buyer. Although I routinely reject diamonds that contain inclusions like knots, cavities and twinning wisps, the cavity in this particular instance would be the least of my concerns given the extent of the feathers.

While the visibility of inclusions is certainly something to consider when evaluating a diamond for purchase and presentation, the extent of the inclusions in terms of the potential durability risk to the diamond should also be taken into account. The extent of the feathers within this diamond might not pose an immediate risk to the diamond during the initial setting process, but may extend with minimal impact to the diamond or during dismount and remount at a later date. Just my two cents, do with it what you will

 

[Defender]

Thanks Todd for your efforts in illustrating these inclusions.

It seems that you are concerned about the corner feathers with respect to breakage issues. I certainly understand that this is really an important issue. You seem to be implying that you would probably not recommend this stone based on the GIA plot. I imagine that the only way to verify this issue will be to have a qualified gemologist take a look at this stone to verify the nature of these feathers.

I also continue to wonder if the 1.08 ratio is a negative on this Emerald. It is neither a Square/Asscher shape or a true Emerald shape.... Is this a negative in valuation of this stone??

 

[niceice]

Date: 4/13/2006 2:30:10 PM
Author: Defender
Thanks Todd for your efforts in illustrating these inclusions.

(1) It seems that you are concerned about the corner feathers with respect to breakage issues. I certainly understand that this is really an important issue. You seem to be implying that you would probably not recommend this stone based on the GIA plot. I imagine that the only way to verify this issue will be to have a qualified gemologist take a look at this stone to verify the nature of these feathers.

(2) I also continue to wonder if the 1.08 ratio is a negative on this Emerald. It is neither a Square/Asscher shape or a true Emerald shape.... Is this a negative in valuation of this stone??

(1) Exactly. It''s difficult (more or less impossible) to determine the extent of the inclusions "off paper" but knowing how to align the plotting diagrams from top to bottom is an excellent start for figuring out whether a diamond is even worth bringing in for evaluation... You could have Blue Nile send the diamond to one of the independent Gemologists listed on the Resources / Appraisers link here on PS and have that person evaluate the diamond and determine the extent of the feathers and determine whether they pose a durability risk. Paper plots are a good start, but nothing beats a hands-on evaluation and a few good photographs.

(2) It''s a matter of personal preference, I personally like my emerald cuts to look more like a traditional emerald in the range of 1.50:1.00 to 1.60:1.00 and my Asschers to be within 1.00:1.00 to around 1.00:1.03 or so, but it''s all in the eye of the beholder. There is a pretty cool tool on David Atlas''s site Cool Tool that will help demonstrate the shape of any fancy shape diamond that you are looking at, check it out and proceed accordingly.

 

[RockDoc]

When attempting to judge plot diagrams one has to keep in mind that they are one dimensional attempting to image what is actually a three dimensional item.

Inclusions drawn on the crown side, may actually be deep in the stone. Feathers that appear to near the edge may in fact break the girdle surface.

Feathers drawn as lines may from the opposite view open and spread being far more noticeable that the plot would indicate.

Plus is there is associated strain or stress or tension from the strain spreading through the stone, a true understanding of what is being anticipated might be far from a factual interpretation.

NO ONE... can tell you these things with any certainty without PERSONALLY SEEING THE STONE.

FLAWLESS STONES can have stress or strain present, and as such is NOT SHOWN on any major lab''s report.

I have been told that GIA DOES plot strain centers, but that is kept in THEIR file only and not shown on the reports that they issue. ( Wonder why?)


Rockdoc

 

[adamasgem]

Three Things:
1) a 66% table doesn't seem to me to be like an Assher cut, which would be a high crown, smaller table stone
2) What MAY BE MISSING on the plot, and what you see a lot on GIA papered fancy shapes, are so called "NON CALLABLE" extra facets, which may or not be present..
3) The proximety of the crown cavity to the girdle may be a setting problem, and may not be able to be hidden with a prong, therefore, it is going to collect junk/dirt, and just become more visible.. SI1 may be a little generous for this stone

 

[Richard Sherwood]

Hi Defender. Seems that you''ve found a stone which might be a "sleeper" (looking better than it''s graph indicates), or a "problem stone".

It looks like a 50/50 toss to me...

It''s definitely going to be more squarish than rectangularish. Like Marty points out, the 66% table is going to keep it out of the classic Asscher category and put it into the "squarish" rectangular emerald cut territory.

If you like the "squarish" look, this might be worth checking out. As RockDoc points out, you''re never going to know with a stone like this until it''s viewed personally or through an expert''s eyes.

Nice to see the discerning eye of Todd Gray at work on the forum again...

 

[Garry H (Cut Nut)]

Date: 4/13/2006 8:29:53 PM
Author: Richard Sherwood
Hi Defender. Seems that you''ve found a stone which might be a ''sleeper'' (looking better than it''s graph indicates), or a ''problem stone''.

It looks like a 50/50 toss to me...

It''s definitely going to be more squarish than rectangularish. Like Marty points out, the 66% table is going to keep it out of the classic Asscher category and put it into the ''squarish'' rectangular emerald cut territory.

If you like the ''squarish'' look, this might be worth checking out. As RockDoc points out, you''re never going to know with a stone like this until it''s viewed personally or through an expert''s eyes.

Nice to see the discerning eye of Todd Gray at work on the forum again...

I agree with Rich - and it could cost you money to find out if this is a good stone.

At best it certainly will look more like a square emerald than an asscher.

A critical thing to kno is if the culet has a keel - or it comes to a point.

(BTW how sad that GIA in the 3rd millenium can not describe diamonds (eg radiant, princess etc are called sill names - and the images they use are just plain dopey)