*Is An Inclusion An Inclusion?...Expert Advice Welcome!*

[AGBF]

I wanted to start a new thread rather than to continue a threadjack of another thread, but this topic started here:

Thread on Inclusions Started Here...[URL='https://www.pricescope.com/community/threads/my-new-1-5-i-coloured-princess-is-giving-me-doubts.192474/#post-3505329#p3505329']https://www.pricescope.com/community/threads/my-new-1-5-i-coloured-princess-is-giving-me-doubts.192474/#post-3505329#p3505329[/URL]

If one wants to get the background on what started the debate, one should probably visit that thread.

My question is whether a diamond that is graded SI1 is worse and worse in terms of clarity as it gets larger. The reason for this would be "that as the stone gets larger, the grading inclusions naturally have to increase proportionally as well... i.e. a 'very small' inclusion takes up a certain proportion of the stone, as viewed through the table at 10x; so too an SI grading will be proportionally larger, in keeping with the larger stone...this means that an SI grading may be more easy to spot..."

Or is an inclusion an inclusion? I think we have had enough exchange of ignorance (I hope my fellow non-professionals pardon my including them with myself in the group of the ignorant among those speculating on the grading works). Would someone who knows how the grading system works in practice please enlighten us?

Deb/AGBF

 

[MissGotRocks]

I'm not sure I agree with that. I think the grading depends on the number, size and placement of the inclusions. A larger stone - just because it has larger area - may show more inclusions than a smaller one but I think it's hard to generalize on this.

Let's hope that the real experts/appraisers chime in on this one - Lord knows I'm not either of those two things!

 

[Smith1942]

I am also very curious about this, since I have heard a number of times that, in general, the larger the stone, the more important clarity becomes. One example of this is Lumera Diamonds' education site, bottom of the linked page: http://www.lumeradiamonds.com/diamond-education/diamond-clarity

"The larger the diamond, the easier imperfections are to detect; therefore Clarity becomes more important. For diamonds over 2 carats, a clarity grade of VS2 or higher is the safest bet for avoiding any signs of visible inclusions. In diamonds between 1 and 2 carats, clarity grades of SI1 or better will not have inclusions easily visible to the naked eye. In diamonds under 1 carat, clarity should be considered the least important of the traditional 4 Cs."

Maybe the idea that you should stay in the higher clarity grades for larger diamonds is just a myth. I would be very interested to know, especially since I'm sure I've seen this advice a few times on PS too. Not that I'm in the market for a large diamond.

If this isn't true about clarity, what about the assertion in the linked thread that colour is also easier to see in large diamonds? Would that also be an erroneous statement?

If not, it would be fascinating to know why clarity isn't proportionally more important in larger diamonds, but colour is.

And if Lumera Diamonds is wrong, someone should let them know!

Here's hoping the experts will come along and chime in.

 

[shimmer]

I was posting in the other thread before I saw this, I will copy my post over here:


Having just completed my diamond grading lab at GIA, I can attest that GIA teaches (rather implicitly) that clarity grading is done proportionally to the diamond size, just as colour grading of larger stones is done with a larger master set ( a 2 ct I colour master will appear to have more body colour than a 1 ct I colour master).

However, since size of inclusions is only one-fifth of the clarity grade (nature, relief, position and number being the others), it must be considered concurrently with the other factors so it is extremely difficult to create a blanket statement or conclusion that just considers the size of an inclusion in terms of the clarity grade.

 

[trilliantjewels]

i diamond is graded on the placement of the inclusion and the type of it if its a center clear stone then a 3 ct stone will also look clean as all the inclusion would be on the sied

 

[msop04]

i diamond is graded on the placement of the inclusion and the type of it if its a center clear stone then a 3 ct stone will also look clean as all the inclusion would be on the sied

I thought they were graded on the type and not the placement, hence finding eye-clean SI1, SI2, and I1 clarity stones (table is clear but larger inclusion on the outer edge).

 

[MissGotRocks]

I was posting in the other thread before I saw this, I will copy my post over here:


Having just completed my diamond grading lab at GIA, I can attest that GIA teaches (rather implicitly) that clarity grading is done proportionally to the diamond size, just as colour grading of larger stones is done with a larger master set ( a 2 ct I colour master will appear to have more body colour than a 1 ct I colour master).

However, since size of inclusions is only one-fifth of the clarity grade (nature, relief, position and number being the others), it must be considered concurrently with the other factors so it is extremely difficult to create a blanket statement or conclusion that just considers the size of an inclusion in terms of the clarity grade.

Ding, ding, ding, ding - we have an answer! Thank you very much for clarifying this!

 

[Smith1942]

Here is something interesting from AGSL:

http://www.agslab.com/education-diamond-clarity-grade.php

So you don't have to read the whole thing, it says under Size:

"Also, the size of the inclusions and their cumulative effect are considered relative to the size of the stone."

and, at the bottom, under Tips From AGSL Laboratories Rock Stars:

"Diamond size has an effect on clarity. It’s easier to see an inclusion in a larger diamond than in a small one." This would seem to bear out what I meant, although perhaps I wasn't very clear. ETA: It's interesting the way that AGS presents this as a fact - i.e., they don't say "It CAN be easier to see an inclusion in a larger diamond", they say it IS easier to see.

But of course, I agree with Deb that each diamond needs to be assessed. As I said on the other thread, an individual's perception of what's an accpetable clarity to them can be affected by eyesight and other subjective factors. My comment was a general one based on all the sources I've seen in the past that say diamond size is indeed - or at least can be - a factor in clarity, although AGS seems pretty sure of this.

I had read it a number of times since I became interested in diamonds - perhaps first on the AGS website.

 

[Rockdiamond]

All of this must be taken in context.
Yes, it's true that larger SI stones may allow easier viewing of an imperfection- yet making any sort of blanket statement is a disadvantage to consumers.
Here's why I say that:
By promoting the idea that people buying larger stones need to go with a higher clarity, it's kind of like an automatic upsell.
While it's true that some larger stones of SI clarities may possess imperfections that can be seen naked eye, it's not true in all cases- or even a majority.
But heck- many dealers want to convince every consumer they need a flawless.
Same is true with color.

I am sensitive to this fact as a grader- and as a seller.
So many people call with the mistaken impression an SI stone MUST look worse than a VS.
There are many eye clean stones above 2cts which are accurately graded SI, and may be visually identical to an Internally Flawless stone.

There are also cases of larger VS stones with imperfections that are visible naked eye

 

[AGBF]

If this isn't true about clarity, what about the assertion in the linked thread that colour is also easier to see in large diamonds? Would that also be an erroneous statement?

Well, you have your answer about color. At least the GIA grading course teaches that color does appear more saturated in larger stones. But no one said anything about what are considered accepted truths here on Pricescope: namely that certain diamond shapes show color more than others. And those accepted truths are the basis for advice given to people for buying one shape of diamond over another. They are told that one shape will show the yellow more in a lower color stone than will another shape stone. Is that a myth?

What is not a myth, and has a lot of scientific evidence behind it, is that the human eye starts to be able to perceive a lot more difference in color when it sees a G range diamond. When it sees a D, E, or F the difference in what it is able to perceive is far slighter. I have forgotten what I have read about this, but I do recall being convinced. That means that not all colors can be treated as equal. Larger F's may be more saturated than larger D's, but how many people are color sensitive enough to tell the difference unless they are side by side? On the other hand, once we get to the other side of a G, the human eye works better on color.

Deb/AGBF

 

[diamondseeker2006]

I think the question has been answered, but I know Garry always cautions people about SI stones being more risky in 3 cts+.

 

[msop04]

What is not a myth, and has a lot of scientific evidence behind it, is that the human eye starts to be able to perceive a lot more difference in color when it sees a G range diamond. When it sees a D, E, or F the difference in what it is able to perceive is far slighter. I have forgotten what I have read about this, but I do recall being convinced. That means that not all colors can be treated as equal. Larger F's may be more saturated than larger D's, but how many people are color sensitive enough to tell the difference unless they are side by side? On the other hand, once we get to the other side of a G, the human eye works better on color.

Deb/AGBF

I would agree that some may be able to detect a very slight difference in color if comparing a D and a G side by side and face down (against a white background), but I find it very difficult to believe that the difference is "a lot more" between those two colors. A lot more from G to J, but not from D to G. Detectable, yes... seeing a lot of difference, no. The GOG video shows this easily. Would you mind posting a link to a few of the many studies showing this? I'd be interested to read them.

Also, a D color is completely clear (by definition, it's totally absent of any color)... so no matter what size the stone, a true D color will still be completely clear whether it's a 1.5 ct or a 5 carat.

**WE MAY NEED TO START A NEW THREAD, IF NECESSARY**

 

[TC1987]

I think it's loads tougher to find an "eyeclean" SI2 or even SI1 large diamond now than it was back in the early days of Pricescope. (Remember all of those wonderful eyeclean SI2s in SMTR back then?) The USA customers have to compete with the rest of the world now, so that's more people worldwide vying for the same eyeclean large diamonds. And it seems to me that unless the USA is mining and cutting diamonds domestically, the best stones could easily be sold elsewhere and never even offered to the USA buyers. More than one PS vendor has said that the SI! and SI2 selection is very picked over nowadays.

Also, the grade creep is noticeable. If cutters and vendors are trying to hold prices the same or relatively stable (like, not do another 35% price hike like happened back in 2008 or so), the only way to get more money for any given diamond without appearing to be doing a price hike is to grade it higher. So, then 2003's eyeclean SI2 might be a high end SI1 now, or something similar. I think that the industry quietly came to that unanimous conclusion a few years ago.

 

[AGBF]

Also, a D color is completely clear ... by definition, it's totally absent of any color

**WE MAY NEED TO START A NEW THREAD, IF NECESSARY**

OK...you start this one! But remember, I love threads on color and I am ready to trump your so-called colorless "D" with a Golconda diamond.

Deb

 

[msop04]

Also, a D color is completely clear ... by definition, it's totally absent of any color

**WE MAY NEED TO START A NEW THREAD, IF NECESSARY**

OK...you start this one! But remember, I love threads on color and I am ready to trump your so-called colorless "D" with a Golconda diamond.

Deb

HA! If you start it, I'll comment!!
I'm very interested in this concept though!

 

[AGBF]

Would you mind posting a link to a few of the many studies showing this?

I wouldn't mind. I just don't know if I can find any. How's that for being able to back up my facts? But never let it be said that I give up on a research project. I once thought that research would be my life. I shall look around. Just give me time. I have a very complicated life nowadays.

Deb

 

[msop04]

Would you mind posting a link to a few of the many studies showing this?

I wouldn't mind. I just don't know if I can find any. How's that for being able to back up my facts? But never let it be said that I give up on a research project. I once thought that research would be my life. I shall look around. Just give me time. I have a very complicated life nowadays.

Deb

Cool! I just read about these Golconda diamonds! Very interesting, indeed! I'll go ahead and start a thread... "Golconda Diamonds..."

 

[AGBF]

Would you mind posting a link to a few of the many studies showing this?

I wouldn't mind. I just don't know if I can find any. How's that for being able to back up my facts? But never let it be said that I give up on a research project. I once thought that research would be my life. I shall look around. Just give me time. I have a very complicated life nowadays.

Well...I hate to report this, but the initial results of my "research" show that ten years ago I thought the same thing I did today, that there was some magical space around the color G where the human eye started to perceive color differently. The truth is that all it proves is that sometimes someone (in this case, I) gets an idée fixe and even after he has had it proven to him that the idea is nonsense, he clings to it. I was wrong about the spot around the color G in 2003 and back in 2003 someone showed it to me, but since then I forgot. (Sorry.) Now I went back to the old thread and it refreshed my memory. There's a chart by Marty Haske in the thread about color. It shows where the human eye actually perceives differences in color.

Old Thread On The Human Eye And Color...[URL='https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2']https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2[/URL]

Deb/AGBF

 

[arkieb1]

My pet thing is body hue and body colour in diamonds - something that most people either ignore or don't know about or understand at all.... the reason why you can have a yellow looking "I" a grey looking "I" or a white looking "I", a pink looking "I" a yellow/green looking "I" and so on. I never cease to be amazed that certain underlying tints like a brownish pink for example can almost disappear and make a stone face white to the average person yet another stone with the same colour grading can look quite yellow to the average person.

I've also seen a grey looking "D" a blue looking "D" a white looking "D" and a green looking "D".

 

[Smith1942]

What's a Golconda diamond? Don't answer that; I'll look it up. Sounds very interesting.

I find diamond colour a fascinating topic, more so than clarity. I became interested in it when I bought a D diamond from James Allen. I always thought my I e-ring was quite white, and it appears so on its own, but when you put my D next to it the stone is instantly lemon. So because I have a D and an I, I like spending time trying to spot the grades in between, in the rest of my jewellery.

I'm quite colour sensitive. I do a lot of typographical spotting in my work - sometimes I have to decide whether a period is in italic font or not and although my distance vision is crap, I've got very good up-close vision. (Of course, if I was tested in a lab situation, who knows if I'd turn out to be correct about my colour-spotting!) But anyway, notwithstanding the diamond's cert, doesn't the appearance of a stone depend to some extent on the quality of the beholder's eyesight? Even with my correct lens prescription, my husband's distance vision is better than mine, for example.

My 0.70 diamond e-ring is an AGS-graded Si1. There's a black carbon mark on the table. It's tiny, of course. Generally, you can't see it without a loupe. But if the light is really, really bright, since I know it's there, I can see it from a few inches away without a loupe. Luckily, I don't mind it at all. (I do wish the diamond was higher colour, though.) My SA at Tiffany told me that Tiffany will not accept any diamond with a black inclusion on the table - that all inclusions have to be hidden in the setting at the edge. I have no idea if that's true or not, but I can vouch for the fact that the same isn't true at HoF!

Arkie, I didn't know that about tones and hues. I've really only analysed my own diamonds. Again, very interesting.

 

[WinkHPD]

Would you mind posting a link to a few of the many studies showing this?

I wouldn't mind. I just don't know if I can find any. How's that for being able to back up my facts? But never let it be said that I give up on a research project. I once thought that research would be my life. I shall look around. Just give me time. I have a very complicated life nowadays.

Well...I hate to report this, but the initial results of my "research" show that ten years ago I thought the same thing I did today, that there was some magical space around the color G where the human eye started to perceive color differently. The truth is that all it proves is that sometimes someone (in this case, I) gets an idée fixe and even after he has had it proven to him that the idea is nonsense, he clings to it. I was wrong about the spot around the color G in 2003 and back in 2003 someone showed it to me, but since then I forgot. (Sorry.) Now I went back to the old thread and it refreshed my memory. There's a chart by Marty Haske in the thread about color. It shows where the human eye actually perceives differences in color.

Old Thread On The Human Eye And Color...[URL='https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2']https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2[/URL]

Deb/AGBF

Interesting to see that AGBF. One thing we all need to remember is that not all human eyes are the same. At one point in my life I was able to score a 98% on the Munsell color test. I was in my forties then. Now at 66 it will be less, but I do not know how much less. Had I been tested in my twenties I might well have scored 100% but I will never know.

When I studied pearl grading (when I was in my twenties), my instructor informed me that as good as my eyes were I would never grade as well as my Japanese and Chinese friends, as they had more rods and cones in their eyes and could discern more minor color differences that I would ever be able to do. I have always wondered if that was why my Chinese and Japanese clients are so much more concerned about color than my American clients. Is it truly a perceived color difference, or is it truly a cultural difference? Most likely it is a combination of both.

So, AGBF, could it be that you were both right and wrong about the G color, depending on which set of eyes were looking at the gem? I know that my ability to see color changes throughout the day too. If I have had a bad night's sleep my eyes are less able to discern minor differences than after a good night's sleep, and also later in the day. We were taught in my diamond grading class back in 1975 not to color grade late in the day or when we were overly tired.

It is, a very interesting topic, with no easy or quick answers!

Wink

 

[distracts]

sometimes I have to decide whether a period is in italic font or not

WHAT. NO. HOW CAN YOU EVEN TELL THAT??????

 

[Smith1942]

sometimes I have to decide whether a period is in italic font or not

WHAT. NO. HOW CAN YOU EVEN TELL THAT??????

I have clients who are extremely fussy - old, venerable publishing houses which are today just imprints of companies like Random House, who pride themselves on absolute typographical accuracy (as well as other types of accuracy, of course.) So, if you're following a style which says that all punctuation after italic words must also be in italics, it would be bad form for the commas to be in italic but not the periods.

If the type is on the larger side, it's not so hard. But if it's on the smaller side, I have a hilarious magnifier that looks like a crystal ball.

Also helps that I've got very good up-close vision.

Sometimes, in an electronic document you can check the coding and see it that way. But often I'm proofing on paper. ETA: Sometimes also you can see an italic and non-italic period close to each other and they look slightly different. I need a bright light - I actually have two spotlights trained on my proofreading desk in addition to the normal lighting. But I can only see my Si1 inclusion in bright daylight.

 

[Smith1942]

Here is something interesting from AGSL:

http://www.agslab.com/education-diamond-clarity-grade.php

So you don't have to read the whole thing, it says under Size:

"Also, the size of the inclusions and their cumulative effect are considered relative to the size of the stone."

and, at the bottom, under Tips From AGSL Laboratories Rock Stars:

"Diamond size has an effect on clarity. It’s easier to see an inclusion in a larger diamond than in a small one." This would seem to bear out what I meant, although perhaps I wasn't very clear. ETA: It's interesting the way that AGS presents this as a fact - i.e., they don't say "It CAN be easier to see an inclusion in a larger diamond", they say it IS easier to see.

But of course, I agree with Deb that each diamond needs to be assessed. As I said on the other thread, an individual's perception of what's an accpetable clarity to them can be affected by eyesight and other subjective factors. My comment was a general one based on all the sources I've seen in the past that say diamond size is indeed - or at least can be - a factor in clarity, although AGS seems pretty sure of this.

I had read it a number of times since I became interested in diamonds - perhaps first on the AGS website.

Re. the second statement...who's going to be brave enough to write to the AGS and tell them not to make blanket comments?

 

[delight]

Here is something interesting from AGSL:

http://www.agslab.com/education-diamond-clarity-grade.php

So you don't have to read the whole thing, it says under Size:

"Also, the size of the inclusions and their cumulative effect are considered relative to the size of the stone."

and, at the bottom, under Tips From AGSL Laboratories Rock Stars:

"Diamond size has an effect on clarity. It’s easier to see an inclusion in a larger diamond than in a small one." This would seem to bear out what I meant, although perhaps I wasn't very clear. ETA: It's interesting the way that AGS presents this as a fact - i.e., they don't say "It CAN be easier to see an inclusion in a larger diamond", they say it IS easier to see.

But of course, I agree with Deb that each diamond needs to be assessed. As I said on the other thread, an individual's perception of what's an accpetable clarity to them can be affected by eyesight and other subjective factors. My comment was a general one based on all the sources I've seen in the past that say diamond size is indeed - or at least can be - a factor in clarity, although AGS seems pretty sure of this.

I had read it a number of times since I became interested in diamonds - perhaps first on the AGS website.

Re. the second statement...who's going to be brave enough to write to the AGS and tell them not to make blanket comments?

Don't see anything wrong with that statement that AGS made.

 

[Smith1942]

Right, that's right, but I said the same thing as AGSL in another thread, which lead on to the analysis in this thread, and consensus seems to be that generalisations are difficult and we're safer not making blanket statements about diamond size and clarity, as a number of posters said, and I agree.

(I don't really mean we should write to AGS - it was a joke!)

 

[msop04]

There's a chart by Marty Haske in the thread about color. It shows where the human eye actually perceives differences in color.

Old Thread On The Human Eye And Color...[URL='https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2']https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2[/URL]

Deb/AGBF

Thanks for posting this AGBF -- very interesting... I would've imagined that the difference could be seen before the range suggested. Personally, I start to see a difference at I color when compared to D-E-F stones.

 

[msop04]

When I studied pearl grading (when I was in my twenties), my instructor informed me that as good as my eyes were I would never grade as well as my Japanese and Chinese friends, as they had more rods and cones in their eyes and could discern more minor color differences that I would ever be able to do. I have always wondered if that was why my Chinese and Japanese clients are so much more concerned about color than my American clients. Is it truly a perceived color difference, or is it truly a cultural difference? Most likely it is a combination of both.

Wink

I remember this from school, but had never "put 2 + 2 together," so to speak. This totally makes sense to me -- maybe that ability to discern more color differences can be credited to helping shape the diamond culture? Hmmmmm....

 

[AGBF]

There's a chart by Marty Haske in the thread about color. It shows where the human eye actually perceives differences in color.

Old Thread On The Human Eye And Color...[URL='https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2']https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2[/URL]

Thanks for posting this AGBF -- very interesting... I would've imagined that the difference could be seen before the range suggested. Personally, I start to see a difference at I color when compared to D-E-F stones.

We may be speaking at cross purposes here. I was not suggesting, and I know Wink was not, that we could not perceive differences between a D and and E and E and an F, at all. That is why there are master stones and why GIA grades for color: because we trust that some of us can perceive the slight differences between these colors with our eyes.

However, the big leap which I kept insisting comes at the color G, does not come there. It comes lower down the color scale. That is the point at which the human eye's potential for perceiving color is suddenly realized to its fullest extent, at least when it comes to the eyesight qualities needed to observe diamond color (I don't know a better way to word this).

This is where Marty Haske's chart shows that G is not where the action is. (I'm trusting him because I don't want to try to challenge that chart. No way am I going to go up against that chart. That chart has my complete confidence.)

Deb

 

[WinkHPD]

There's a chart by Marty Haske in the thread about color. It shows where the human eye actually perceives differences in color.

Old Thread On The Human Eye And Color...[URL='https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2']https://www.pricescope.com/community/threads/visible-difference-between-f-g-colours.10161/page-2[/URL]

Thanks for posting this AGBF -- very interesting... I would've imagined that the difference could be seen before the range suggested. Personally, I start to see a difference at I color when compared to D-E-F stones.

We may be speaking at cross purposes here. I was not suggesting, and I know Wink was not, that we could not perceive differences between a D and and E and E and an F, at all. That is why there are master stones and why GIA grades for color: because we trust that some of us can perceive the slight differences between these colors with our eyes.

However, the big leap which I kept insisting comes at the color G, does not come there. It comes lower down the color scale. That is the point at which the human eye's potential for perceiving color is suddenly realized to its fullest extent, at least when it comes to the eyesight qualities needed to observe diamond color (I don't know a better way to word this).

This is where Marty Haske's chart shows that G is not where the action is. (I'm trusting him because I don't want to try to challenge that chart. No way am I going to go up against that chart. That chart has my complete confidence.)

Deb

I certainly was not, but let us not forget Dear Lady, that we color grade diamonds from the side against a white background in light that is supposed to be free of fluorescence. Thus even minor variations are visible. However, table up, it is much more difficult to see and that may well be below the G range where most of us can detect it easily. It is table up where the difference in our visual acuity will most strongly be tested.