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THIS is SI1?

VRBeauty

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s11-2.png

or this?


img_25.jpg

Or this?

img_26.jpg

So I was searching for SI1 diamonds in a certain price range, and these were among the options that showed up. These are all in the .8 ct range, GIA-certified as SI-1. I had always thought it was pretty safe to recommend SI-1 diamonds for consideration, but now I'm re-thinking that. Could any of these possibly be reasonably eye-clean in real life?

Seriously, what are the parameters for grading a diamond as SI-1?
 

MollyMalone

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GIA clarity grading scale here; note the consistent references to 10x magnification:
http://www.4cs.gia.edu/EN-US/diamond-clarity.htm

As for whether any of them might be eye-clean, reduce those posted pics down in size so the diamonds are just 6 mm wide -- and remember that eye-clean is not defined (by any vendor I know of) by what's seen when the stone is as close as 4-5 inches from your scrutinizing eyeballs ;))

Here's a 2009 PS article on eye-clean that includes the varying responses at that time from different vendors & appraisers;
https://www.pricescope.com/journal/what_eye_clean_diamond
 

centrifuge41

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None of these look like good SI1's. I'm guessing that I'd probably see the inclusions in all of them :o

Good SI1's might have more feathers, clouds, or twinning wisps. Dispersed non-black inclusions that are harder to spot. Or, if there's a single black crystal farther out from the table, that's prongable, that'd be great too.
 

Texas Leaguer

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The top two appear to be the same stone if you look closely at the inclusion pattern. I have a hard time believing that got Si1 from a respectable lab!

As clarity categories go down through the scale they broaden out so that Si1 and especially Si2 can have a wide range of clarity characteristics, some that look surpringly clean and others that look like the example above.
 

Rockdiamond

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Sharp eye Bryan!!
I agree- the first two images must be the same stone.
I also agree that, based on that photo it's hard to believe that such a stone would grade SI1.

BUT- I will say that the new cameras in use have created an issue with SI and even some VS diamonds.
There are stones that look horrible in the hi def camera shot, yet are totally eye clean in person.

Remember, clarity grading has nothing to do with visibility of imperfections, as opposed to the presence of imperfection.
For example the first diamond shown ( the one with the duplicate image)- it's quite possible there's actually half as much black carbon as the picture shows. Many imperfections "repeat"- IOW, although there's only one crystal in a given stone, it can look like multiple crystals as it reflects around the stone.
That would explain the first stone getting an SI1 grade.....
 

Texas Leaguer

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Rockdiamond|1447365157|3948936 said:
Sharp eye Bryan!!
I agree- the first two images must be the same stone.
I also agree that, based on that photo it's hard to believe that such a stone would grade SI1.

BUT- I will say that the new cameras in use have created an issue with SI and even some VS diamonds.
There are stones that look horrible in the hi def camera shot, yet are totally eye clean in person.

Remember, clarity grading has nothing to do with visibility of imperfections, as opposed to the presence of imperfection.
For example the first diamond shown ( the one with the duplicate image)- it's quite possible there's actually half as much black carbon as the picture shows. Many imperfections "repeat"- IOW, although there's only one crystal in a given stone, it can look like multiple crystals as it reflects around the stone.
That would explain the first stone getting an SI1 grade.....
Clarity grading does in fact have something to do with visibility- it's an assessment of how easy or how difficult it is to locate and see inclusions. But that assessment is made under 10 power magnification. Obiously, the bigger and more numerous inclusions are the easier they are for the grader to see. Relief is also a factor - how starkly an inclusion contrasts with the background. Higher relief, the easier it is to see. Whether the stone is eye-clean or not is not a specific criterion. Repeaters (inclusions that reflect) will tend to lower the clarity grade.
 

Rockdiamond

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We have different experiences in this area Bryan. I have seen quite a few I1's with less visible imperfections than other SI1's
Based on looking at many thousands of GIA graded diamonds, a given sized crystal is going to get the same grade no matter where it's located. So it's based on the presence of the imperfection, not the visibility.
 

gr8leo87

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Relief, Location, type. These factors can set VSs apart from SIs. Two stones similar sized inclusions one under the table and other hidden in the crown can contribute towards a stone for a SI grade. Both of those stones appear to be cut lucky SIs.

I can't stress on the fact enough that how important pictures are for consumer to buy diamonds. Buying unseen and ending up with dogs will cost you emotionally apart from financially.
 

Rockdiamond

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Lucky SI1's are possible because visibility is not a defining aspect.....

About pictures- I agree buying blind is not desirable.....but if a picture makes a diamond look much worse than it is in reality, that is an issue as well.....
 

Texas Leaguer

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Rockdiamond|1447368093|3948953 said:
Lucky SI1's are possible because visibility is not a defining aspect.....
In fact, clarity grading is ALL about visibility. And the various factors that have been mentioned affect visibility. When you get into the imperfect range durability also becomes a factor.
 

Rockdiamond

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Part of this discussion is about semantics...
I've developed a manner of teaching consumers about clarity based on a huge void in understanding of clarity grading.
Typical discussion which highlights this void
Consumer: "I'm looking for a 2ct diamond- it has to be really shiny, so do not show me any SI stones"

In terms of visibility and grading: Have you ever seen an I1 diamond that forced you to look -hard- with a loupe to find the imperfection?
I have. Rare, but they exist in I1- there's more like this in SI2, and more yet in SI1

About GIA practices- I'm not basing my statements on GIA literature- rather practical experience with GIA graded diamonds.
AS good as GIA is- there's areas where the published literature is conflicting.
 

Texas Leaguer

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Rockdiamond|1447371070|3948969 said:
Part of this discussion is about semantics...
I've developed a manner of teaching consumers about clarity based on a huge void in understanding of clarity grading.
Typical discussion which highlights this void
Consumer: "I'm looking for a 2ct diamond- it has to be really shiny, so do not show me any SI stones"

In terms of visibility and grading: Have you ever seen an I1 diamond that forced you to look -hard- with a loupe to find the imperfection?
I have. Rare, but they exist in I1- there's more like this in SI2, and more yet in SI1

About GIA practices- I'm not basing my statements on GIA literature- rather practical experience with GIA graded diamonds.
AS good as GIA is- there's areas where the published literature is conflicting.
What you may see in the market and the impressions you have about individual stones and whether you agree or disagree with the grade, does not change the fact that graders are trained in a highly structured way to grade clarity in the lab.

It is about assessing the degree to which a diamond has visible inclusions at 10X. Size, number, location, nature, and relief all affect the the degree to which inclusions can be seen by the grader. A pinpoint gets a VVS1 because it is extremely difficult for a trained grader to locate and resolve at 10x. A black crystal under the table gets an Si1 because it is relatively easy for a trained grader to see at 10x. The same crystal located off to the side and camouflaged under the crown facets might get a VS2 because it is somewhat more difficult to see.

Clarity grading is done by humans. There is an inherent element of subjectivity to the skill. That is why there is an accepted one grade plus/minus tolerance between labs or even within the same lab. And that is why dealers often challenge lab results and occassionaly win an upgrade when the stone is reviewed by senior graders. The same is true for color grading.
 

Rockdiamond

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Look at the implications:
If consumers are led to believe that VS stones are more "shiny" than SI stones, the net effect is that they are being pushed toward higher priced stones, or smaller stones for the same money.
I love VVS or IF stones.
Of course I understand why people love them.
But in discussions about what diamond to buy, I find out what the buyer wants.
When people call and ask for a VVS stone, I always discuss clarity with them.
Many of the shoppers just want to make sure they get a great looking stone. Many find they are better served with an eye clean SI1 once they have a better understanding of how clarity grading works. And it's relationship with color carat weight and cut.

About GIA grading:
Clarity grading is indeed about human judgment.
It's not based on a formula- it's not done by counting how many imperfections there are- or looking at the stone arm's length to see how it really looks.
After looking at thousands and thousands of diamonds graders get an intuitive feel for the grades. Not before. No amount of book learning will get this job done. Once properly trained, most graders will agree in most cases. The borderline cases will always be judgement calls.

I was trained to grade diamonds at Harry Winston in the late '70's- at the time the clarity scale had all the GIA grades - but with a number instead of GIA nomenclature (VVS, VS etc.)
The scale went
6-2-3-4-9-5-7-8- 8 Special
6 being IF, 7 being SI2, 8 being SI3 ( if there was such a thing)
8 Special was divided into subcategories - I1's of different values.

It was an easy transition when I started grading diamonds at other places where GIA grading was the norm.
Nowadays I usually grade the stone before we send them off to GIA. I get it right about 80% of the time.
I base my statements about GIA grading on that experience as opposed to any published literature on grading techniques or methods.
 

Rockdiamond

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VRBeauty|1447346940|3948807 said:
s11-2.png

or this?


img_25.jpg

Or this?

img_26.jpg

So I was searching for SI1 diamonds in a certain price range, and these were among the options that showed up. These are all in the .8 ct range, GIA-certified as SI-1. I had always thought it was pretty safe to recommend SI-1 diamonds for consideration, but now I'm re-thinking that. Could any of these possibly be reasonably eye-clean in real life?

Seriously, what are the parameters for grading a diamond as SI-1?

About the two diamonds in particular and the boundaries of SI1:
The image with the numerous and dispersed carbon: This could actually be a smaller number of carbon spots placed in a manner that causes them to repeat around the diamond.
If they are small and there's not that many, it might get SI1 if the grader was lenient.

The stone with one larger booger- if it got SI1 it's a very lucky call. Just based on the carbon spot in the center, most graders would give it SI2. But not by all that much IMO. So it's a borderline call.
As I've been saying the visibility of the spot will not determine the grade, the size will.
From the picture it looks as though you could see the spot naked eye.
If the spot was located closer to the girdle it's possible for a spot that size to totally disappear to the naked eye. If the exact same spot was placed somewhere it was harder to see, that would not change the grade- unless the grader was strict and it got SI2.
I'm sure you can find some SI1's that look better than other VS2's as well.
 

VRBeauty

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Thanks everyone for the responses and the discussion. My tendency is to suggest SI1's for PS searchers working on limited budgets - It's good to know that these examples are likely outliers. Nonetheless, to GR8Leo87's point this definitely reinforces (for me) the need to see photos of the actual diamonds being considered, as well as the need to work with a vendor that you trust to give an honest assessment of whether a stone is "eyeclean."

In case anyone is curious, here are the links. It's just happenstance that these diamonds were listed on the James Allen site - it's the GIA grading standards I was asking about.

Dalmation diamond: http://www.jamesallen.com/loose-dia...-h-color-si1-clarity-excellent-cut-sku-742141

The *ahem* booger diamond: http://www.jamesallen.com/loose-dia...-j-color-si1-clarity-excellent-cut-sku-661049
 

gr8leo87

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bryan.boyne.gg said:
Rockdiamond|1447368093|3948953 said:
Lucky SI1's are possible because visibility is not a defining aspect.....
In fact, clarity grading is ALL about visibility. And the various factors that have been mentioned affect visibility. When you get into the imperfect range durability also becomes a factor.
I suppose you mean visibility under the loupe? And not naked eyes?

there can be a visually eye clean SI and non eye-clean VS2.
 

ChristineRose

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The booger is very flat. It's all but invisible from some angles. It's still right under the table though.

The dalmatian I can't understand. You can see plenty of mirroring in the video but there's still plenty of spots. Maybe the dispersiveness of the pattern made a difference.
 

oldminer

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I'm sure Rockdiamond can clarity grade diamond very much to the GIA lab results. Based on his experience and familiarity with the market it would be difficult to think otherwise. What RockD may not be quite as good at is expressing his personal thinking behind his clarity grading process and putting that very complex set of practices into simple words that the general public would understand and which trained gemologists would equate with the exact wording used by the GIA to teach the clarity grading system.

A great deal of what we have argued and discussed over the years here has been based on the exactness of meaning each descriptive word means to each one of us or how one of us may be using a word which most everyone else thinks is "not quite right" or "incorrect".
Sometimes those arguments have been productive, but frequently these threads make experts appear to disagree more than we actually would if the words being used were GIA standard terminology used in the way GIA uses them. Clarity grading is fairly easy if you look at diamonds and split them 5 ways IF/VVS - VS - SI - I1 - 12/I2. If you split off IF from VVS, it becomes more a scientific challenge than anything of importance to beauty or durability. Once you divide VS to VS1 and VS2, SI to SI1 and SI2, then you have done what makes the entire clarity system more subjective, more subjective and a lot more likely to have grey areas between grades that disagreements will be frequent. 10 grades have much more subjectivity than 5 or 6 and lots more cross-over, grey areas. That's what we work with.

Size of the diamond, relative size of inclusions, actual size of inclusions, relief of inclusions including color of inclusions and relative ease of seeing them under magnification, placement of inclusions, number of inclusions, reflections of inclusions, and external blemishes. All of these "count" in a final grade, but exactly how to weigh the effect of each element is an issue of experience and guidance for quite a period of time, not something done with a calculator.

The two diamonds in the photos look like they are SI to I1 based on the huge magnification being used. If GIA says they are SI1, then who are we to argue it? One or both easily could be SI2 and without GIA documentation many buyers would wan to make them SI2 or even I1 to buy them in advance of a GIA report. That's the purpose of getting the GIA to document them. The sellers do not leave profits on the table and will spend money to get the paperwork first. However, this highlights why buying blind based on paperwork is not 100% safe. Every diamond of importance should be closely examined before purchase by a consumer to be sure that particular stone meets their own internal desires and expectations.
 

Texas Leaguer

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gr8leo87|1447410883|3949165 said:
bryan.boyne.gg said:
Rockdiamond|1447368093|3948953 said:
Lucky SI1's are possible because visibility is not a defining aspect.....
In fact, clarity grading is ALL about visibility. And the various factors that have been mentioned affect visibility. When you get into the imperfect range durability also becomes a factor.
I suppose you mean visibility under the loupe? And not naked eyes?

there can be a visually eye clean SI and non eye-clean VS2.
Correct on both points.
Whether a stone is eye-clean is not a grading criterion.

What matters is how visible the inclusions are under 10x to a professional grader trained in the highly structured skill of lab clarity grading. And an important factor is size relativity. That is, if you were to take the same black crystal in diamond #2 and magically put it in a stone half the size, it would become an Si2. Conversely, if you took it and put in in a stone twice its size it would become a VS2.

This is precisely why eye-clean cannot be a determining factor. In large stones the allowable inclusions, for instance in VS2 grade, are still relatively small to the overall stone, but scale up in actual size and are often big enough to see with the naked eye.
 

Rockdiamond

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Texas Leaguer|1447424582|3949232 said:
gr8leo87|1447410883|3949165 said:
bryan.boyne.gg said:
Rockdiamond|1447368093|3948953 said:
Lucky SI1's are possible because visibility is not a defining aspect.....
In fact, clarity grading is ALL about visibility. And the various factors that have been mentioned affect visibility. When you get into the imperfect range durability also becomes a factor.
I suppose you mean visibility under the loupe? And not naked eyes?

there can be a visually eye clean SI and non eye-clean VS2.
Correct on both points.
Whether a stone is eye-clean is not a grading criterion.

What matters is how visible the inclusions are under 10x to a professional grader trained in the highly structured skill of lab clarity grading. And an important factor is size relativity. That is, if you were to take the same black crystal in diamond #2 and magically put it in a stone half the size, it would become an Si2. Conversely, if you took it and put in in a stone twice its size it would become a VS2.

This is precisely why eye-clean cannot be a determining factor. In large stones the allowable inclusions, for instance in VS2 grade, are still relatively small to the overall stone, but scale up in actual size and are often big enough to see with the naked eye.

Totally agree Bryan. I neglected to clarify that when I wrote "visible" I meant visible to the naked eye.
Great post Old Miner!
 
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