Durability of GIA SI 1

[Rockdiamond]

I do think we would agree it's unusual and very large

Please remember that in my work as a diamond grader I have examined and graded hundreds of thousands of diamonds. Maybe millions.

Based on what I see in the pics, this is not an unusual imperfection - nor is it large.
I am not recommending anyone buy ANY diamond they are not comfortable with.
My words are in the interest of information over fear.

 

[Rockdiamond]

I will add that in our practice we regularly reject Si1 for durability concerns. Many of those stones could probably be set with no mishap. But it makes sense to be conservative.

Bryan, this makes perfect sense. Given the type of diamonds you offer-and the well earned and stellar reputation of your company.
Hypothetically....If you were looking for a blue or pink diamond, do you believe you’d take the same tact?

 

[Karl_K]

Have any other trades members - or consumers participating - experienced breakage in a GIA graded SI1 that was associated with a knot?

I have seen in person a vs graded stone where a knot has come out of stone leaving a largish cavity on the crown.
That's why I dont like them on the crown.
I have also seen several pictures of it happening that others have taken.
If they do come out they can lower the grade of the diamond several grades and the insurance company can argue that it was preexisting.
There is nothing on a grading report that tells you how securely the second stone is held in place.

 

[Karl_K]

Bryan, this makes perfect sense. Given the type of diamonds you offer-and the well earned and stellar reputation of your company.
Hypothetically....If you were looking for a blue or pink diamond, do you believe you’d take the same tact?

With a blue or pink I would explore how secure the knot is in the stone.
Does it move? How much is exposed vs how much is covered? location?
What effect would it coming out have on value?
Overall impressions then decide
With a much more common stone, why bother taking the risk what ever it might be?

 

[yssie]

This is a great thread.

I’m waiting for someone to pull out the one specimen in the world that has the inclusion equivalent of an I-beam

 

[Texas Leaguer]

Bryan, this makes perfect sense. Given the type of diamonds you offer-and the well earned and stellar reputation of your company.
Hypothetically....If you were looking for a blue or pink diamond, do you believe you’d take the same tact?

I would probably be even more conservative in that case considering the money involved. As @sledge mentioned, proper risk assessment involves a calculation of BOTH the chances of mishap and the potential loss or gain.

 

[Rockdiamond]

I have seen in person a vs graded stone where a knot has come out of stone leaving a largish cavity on the crown.

Interesting Karl!!
Did you see the stone before and after?
Of course, I've seen VS stones with knots- but by definition, the knot is tiny in a VS stone.
My point is- if there's a large cavity in the crown of a formerly graded VS diamond, I can't imagine how the VS sized imperfection could have caused it.
I've also seen stones where a knot or other imperfection caused a cavity on the skin of the diamond. But I can't remember one that happened due to a person wearing the diamond- rather it happened on the wheel, while the diamond was being polished.
Damage to diamonds on the cutting wheel is fairly common.
In terms of inspecting knots, and other imperfections on stones under consideration- blue pink, or any color: I can't recall an imperfection of any sort in a stone that "moved"....but I've seen many that reached the surface.

 

[Rockdiamond]

I would probably be even more conservative in that case considering the money involved. As @sledge mentioned, proper risk assessment involves a calculation of BOTH the chances of mishap and the potential loss or gain.

AH, another science versus mind clean debate....Bryan-my position, based on personal and other's trade experience, is that there's no real risk to an SI1 sized knot.....it's a mind clean issue.
Given that- my experience is that if there's a Red Argyle Diamond with an SI1 sized knot, said knot will have ZERO impact on price versus any other Argyle Red of the same size.
Although maybe discussions like this will have the same effect as the discussions of fluorescence- and then I can buy all kinds of amazing SI1 diamonds with knots at a discount!!

 

[Wewechew]

Interesting Karl!!
Did you see the stone before and after?
Of course, I've seen VS stones with knots- but by definition, the knot is tiny in a VS stone.
My point is- if there's a large cavity in the crown of a formerly graded VS diamond, I can't imagine how the VS sized imperfection could have caused it.
I've also seen stones where a knot or other imperfection caused a cavity on the skin of the diamond. But I can't remember one that happened due to a person wearing the diamond- rather it happened on the wheel, while the diamond was being polished.
Damage to diamonds on the cutting wheel is fairly common.
In terms of inspecting knots, and other imperfections on stones under consideration- blue pink, or any color: I can't recall an imperfection of any sort in a stone that "moved"....but I've seen many that reached the surface.

I assume the companies that own the rough during cutting have insurance for this?

 

[Rockdiamond]

I assume the companies that own the rough during cutting have insurance for this?

They wish!!
Maybe there are instances where insurance is purchased on a case by case- but as a general rule, it's basically a cost of doing business.

 

[Wewechew]

They wish!!
Maybe there are instances where insurance is purchased on a case by case- but as a general rule, it's basically a cost of doing business.

Oh wow!!!!!! Ouch!

 

[Rockdiamond]

We have a stone which was a totally clean diamond till it was 99% finished on the wheel... then BANG!!!
It went from being a VS1 to an I2
The diamond was a brown stone- and brown diamonds are notoriously brittle during cutting. But again, to back up my point- we have not seen this sort of thing happen when people are wearing brown diamonds.......

 

[Texas Leaguer]

AH, another science versus mind clean debate....Bryan-my position, based on personal and other's trade experience, is that there's no real risk to an SI1 sized knot.....it's a mind clean issue.
Given that- my experience is that if there's a Red Argyle Diamond with an SI1 sized knot, said knot will have ZERO impact on price versus any other Argyle Red of the same size.
Although maybe discussions like this will have the same effect as the discussions of fluorescence- and then I can buy all kinds of amazing SI1 diamonds with knots at a discount!!

Not so much science, and not so much 'mind clean', as it is just basic common sense.
I would wholeheartedly disagree that a feature like the one we are talking about here would have ZERO impact on price of a high end fancy red.

 

[Karl_K]

Interesting Karl!!
Did you see the stone before and after?

After only and the grading report.

I am not interested in more debate and respect your opinion even if its not the same as mine but I do have a question.
I have never seen a stone with this big a knot and frankly still wonder how its possible.
Have you seen something like this before?
@Texas Leaguer same ? to you!

 

[Rockdiamond]

I would wholeheartedly disagree that a feature like the one we are talking about here would have ZERO impact on price of a high end fancy red.

Bryan- In a comparison between two SI1 diamonds, I have never experienced a difference in price based specifically on the type of imperfection.
Of course, there's better and worse SI1's- which will affect price.
But it's based on visibility, not the specific type of imperfection. Based on my experience.
I used Red as an example as they are so durn rare that even an I1 graded "Red" by GIA is going to cost a fortune. I've seen maybe 10 in my entire career.
I can just imagine the look on a cutters face when he shows me a Red diamond and I ask, " do you have one with a crystal instead of a knot"

 

[Rockdiamond]

snip.... respect your opinion even if its not the same as mine

My brutha!! I echo your sentiments- to the max- total respect.

As far as having seen a stone like this- yes, countless times.....

 

[Texas Leaguer]

In my experience I cannot recall ever seeing a cert with a knot like this.

As we know, every diamond is unique and clarity grades are ranges on a spectrum. And as you drop down on the scale those individual ranges become larger and braoder. Perhaps this one is in the lower range of Si1. But I'm guessing that because of visual appearances, the grader was reluctant to lower the clarity grade any further.

As we also know, clarity grading calls are made by humans and there is naturally some variance. In this case, the grader made an assessment not to place too much emphasis on durability. What we don't know is the extent of the the grader's experience in making that determination.

 

[Rockdiamond]

Bryan- you keep raising the specter of durability. Where’s all the stones that have been damaged due to SI1 knots?
You’re implying that GIA overlooked an important aspect. Except, if there’s no realistic concern, then GIA overlooked nothing. I’m not saying GIA is infallible- maybe I’d call this an SI2 if I saw it in person. But not based on durability.

 

[Texas Leaguer]

Bryan- In a comparison between two SI1 diamonds, I have never experienced a difference in price based specifically on the type of imperfection.
Of course, there's better and worse SI1's- which will affect price.
But it's based on visibility, not the specific type of imperfection. Based on my experience.
I used Red as an example as they are so durn rare that even an I1 graded "Red" by GIA is going to cost a fortune. I've seen maybe 10 in my entire career.
I can just imagine the look on a cutters face when he shows me a Red diamond and I ask, " do you have one with a crystal instead of a knot"

David,
Your first statement is just whacky. Of course price can be affected by type of imperfection, because visual appearance is often affected by type of inclusion. There is a reason why consumers tend to prefer certain types of inclusions over others. Transparent features such as Clouds and twinning wisps (and knots) tend to be less obvious than black crystals or feathers. Demand and therefore Price are affected by those differences in appearance. Most shoppers like Si1 for price point, but require 'eye-clean'. The difference very often revolves type of imperfection.

Clarity grading in the lab is dependent on a number or different considerations regarding inclusions:
Size, number, location, relief, and type. Clarity grading is fairly complex and therefore requires more training and experience than most other routine skills in the lab.

 

[Texas Leaguer]

Bryan- you keep raising the specter of durability. Where’s all the stones that have been damaged due to SI1 knots?
You’re implying that GIA overlooked an important aspect. Except, if there’s no realistic concern, then GIA overlooked nothing. I’m not saying GIA is infallible- maybe I’d call this an SI2 if I saw it in person. But not based on durability.

You are right, GIA is not infallible. Nobody is.

All I am advocating, from a standpoint of consumer education and protection, is to take a conservative approach based upon the information contained in the lab report.

 

[kindred]

@Rockdiamond wrote "Damage to diamonds on the cutting wheel is fairly common."

Do you have an idea as to what percentage of diamonds are damaged on the cutting wheel?

 

[Rockdiamond]

David,
Your first statement is just whacky.

Whacky??? I LOVE IT!!!!
I have not heard that term since the last time I was arrested ...KIDDING!!!
Seriously, please look at what I said
"In a comparison between two SI1 diamonds, I have never experienced a difference in price based specifically on the type of imperfection."
Of course, I've seen prices affected by the nature and placement of imperfections within a grade. But not based solely on the nature of imperfection.
To use the fluorescence comparison- a D/VS1 inert will be x% less than the same stone Medium or strong blue.
In the vast majority of cases, this is true.
But in comparing an SI1 with a knot, versus SI1 with a feather, or crystal, or twining wisps......sure there may be price differences based on specific aspects of a given imperfection in a diamond.
But there's no expectation of a stone with a knot being cheaper than a stone with a feather for that reason alone.

 

[Rockdiamond]

This is a great thread.

I’m waiting for someone to pull out the one specimen in the world that has the inclusion equivalent of an I-beam

Lookie what I found in an SI1 today!!!

 

[sledge]

But in comparing an SI1 with a knot, versus SI1 with a feather, or crystal, or twining wisps......sure there may be price differences based on specific aspects of a given imperfection in a diamond.
But there's no expectation of a stone with a knot being cheaper than a stone with a feather for that reason alone.

I wasn't saying a tiny knot should be discounted more than a tiny feather. I was saying I believe this particular knot to be abnormally large and placed in a position that concerns me.

As such, I view it as a risk and something that detracts from the value of the stone; therefore, IMO, it should be discounted to move it in the market. If I can't get that discount, then I'd pass altogether and spend my dollars on a stone that doesn't cause me concern. Problem solved.

Obviously you view it different. And that's okay. I have respect for your experience and opinion and have found the conversation interesting but no longer wish to debate it.

 

[sledge]

Lookie what I found in an SI1 today!!!

LOL, I had the same thoughts yesterday.

Also, found this....this is how you disguise imperfections....haha

 

[Rockdiamond]

I wasn't saying a tiny knot should be discounted more than a tiny feather. I was saying I believe this particular knot to be abnormally large and placed in a position that concerns me.

I know you said you're done discussing....but in the interest of education:
I can not say with certainty that I would like this stone- or the nature and placement of the imperfection within the grade of SI1.
I might agree that it's a weak SI1- might even agree that a greater discount is in order IF I had the chance to examine the diamond in person.
But the thread was not about that- the tread is regarding durability- and on that particular issue, nothing in evidence indicates any sort of problem whatsoever. Even if I felt that SI2 is more appropriate for the stone that still does not indicate a potential durability issue exists.
Diamonds break. But in my extensive experience, damages are caused by an impact which causes a chip -not based on imperfections. Occurrences of stones actually breaking in two are exceptionally rare.

 

[sledge]

I know you said you're done discussing....but in the interest of education:
I can not say with certainty that I would like this stone- or the nature and placement of the imperfection within the grade of SI1.
I might agree that it's a weak SI1- might even agree that a greater discount is in order IF I had the chance to examine the diamond in person.
But the thread was not about that- the tread is regarding durability- and on that particular issue, nothing in evidence indicates any sort of problem whatsoever. Even if I felt that SI2 is more appropriate for the stone that still does not indicate a potential durability issue exists.
Diamonds break. But in my extensive experience, damages are caused by an impact which causes a chip -not based on imperfections. Occurrences of stones actually breaking in two are exceptionally rare.

No worries.

I think @yssie might get her dream come true. What good does it do to install a beam that functions perfectly on the ground, but fails once it's erected and subjected to stress loads that makes the whole thing come crashing to the ground?

Same deal w/ this diamond. It randomly falling apart under no stress load is not indicative it is free of structural or durability concerns. It just means it hasn't been subjected to a stress load that has caused failure. The real question becomes what kind of a stress load can the stone endure before it experiences failure?

Assuming it's not exposed to loads greater than a normal stone, can the knot withstand those normal loads without failure? I really don't know without further analysis; however, I do know it's an area of concern and the first place I'd look and expect failure to occur.

 

[Rockdiamond]

Sledge- my ONLY goal in participating in this thread is to allay irrational fears.
There's ZERO evidence- or data based on other stones breaking- to indicate that there are any structural implications.
My analogy about the nail in the wall stands.
Will a single nail weaken a sound wall? Yes. Imperceptibly, but yes. Will such weakness lead to wall failure? No, it won't. Stresses can easily cause damage to any wall or diamond. But walls don't fall from a single nail and diamonds don't crack due to SI1 sized internal imperfections.
By all means- skip any stone that has any imperfection you don't like. In general, there's always another alternative. My point about Red diamonds is, there's isn't always an alternative.
But fear of durability on an RBC graded SI1 by GIA is an irrational fear.

 

[diagem]

What is the difference between knots and twinning wisps inclusions?
They are basically the same except perhaps their size and position.
In our cutting world, dividing knots by cleaving and/or cutting can be very challenging. Actually their attachments can be extremely sturdy.

I have been reading this thread and cant help standing by Rockdiamond on his professional judgement and recommendation.

If this diamond is unique in any other property like its faint brown color (which many times display incredible bright appearances), and the knot inclusion looks rather harmless as in the image provided, i would definitely not discount it based on its inclusion solely.

Such diamonds can hide great value.
As far as breakage, there are so many weak spots which will break before such a knot comes apart.

 

[AV_]

As far as breakage, there are so many weak spots which will break before such a knot comes apart.

I'll stand with this: there are quite a few good people who try to grow tough crystals this way. It is much more interesting to hear what you find hard to polish, sure enough.