Questions about CVD vs HPHT and type II vs IIa

[Alybetter]

Hi, looking/hoping for some clarification.
Is there a difference between type 2 and type 2a MMDs?
My first MMD purchase is an HPHT stone that is listed on the IGI cert as ‘Type 2’.
The second and third MMD purchases, which have yet to arrive, are CVD and listed ‘Type 2a’ on the IGI cert. Is there even a type 2? Or is this some anomaly on the certs?
The HPHT stone is has no indication of post growth treatment, according to the cert.

All are graded F color, and I see no mention of colored nuances or undertones on the grading carts, although I’m not sure they would note them.

What’s that about?

 

[Garry H (Cut Nut)]

Type II diamonds are rare in nature - about 2%. Most natural diamonds are type I.
Type IIA is the purest. Type IIB has a tiny bit of boron in the lattice and is blue and conducts electricity.
All (almost all) synthetic, man made or LGD's are type IIA.
Most small diamonds these days are made with HighPressureHighTemperature like superman style.
Most larger diamonds these days are made with ChemicalVapourDeposition in a methane gas chamber and laser microwaves

 

[John Pollard]

My first MMD purchase is an HPHT stone that is listed on the IGI cert as ‘Type 2’.
The second and third MMD purchases, which have yet to arrive, are CVD and listed ‘Type 2a’ on the IGI cert. Is there even a type 2? Or is this some anomaly on the certs?
The HPHT stone is has no indication of post growth treatment, according to the cert.

Hello @Alybetter .

Colorless CVD is reliably Type IIa, so it's identified that way on reports.

Colorless HPHT are widely Type IIa but, depending on process, can have slight traces of boron. To account for this, confirmation of Type II, without stipulating a or b, is the default for colorless HPHT on reports. Further analysis can be done to tease out a/b detail for any given HPHT specimen but involves added time & expense.

Side note: I suspect the HPHT grower who produced the most colorless output I've ever seen - it was nicknamed C color - was using trace amounts of boron. They wouldn't confirm, but that higher-than-D-color impression 'tasted' blue-white.

 

[Rockdiamond]

Most small diamonds these days are made with HighPressureHighTemperature like superman style.
Most larger diamonds these days are made with ChemicalVapourDeposition in a methane gas chamber and laser microwaves

Interesting point Garry....not what I'm seeing on the market...there's both HPHT as well as CVD melee on the market.
CVD slightly more expensive, slightly more color.
HPHD whiter, less costly, but may not test as diamond using a diamond tester.
But this is just "reporting from the ground"

Side note: I suspect the HPHT grower who produced the most colorless output I've ever seen - it was nicknamed C color - was using trace amounts of boron. They wouldn't confirm, but that higher-than-D-color impression 'tasted' blue-white.

Interesting suggestions John- about the Boron.
I agree that some of the HPHT grown stones we're seeing look like "C" color.
From what I understand you can only grow the diamond from a "diamond seed".

Speculating here: If they could introduce Boron, why wouldn't they use that technique to grow blue rough....or introduce Nitrogen to grow yellow rough?


I am not sure and greatly welcome discourse on the subject. There's a lot of bull flying around as the Lab Grown segment has exploded. As an example- seems like everyone and his brother is claiming to be a grower, at the wholesale level.
People I consider to be straight shooters say you can't "add" elements

 

[John Pollard]

Speculating here: If they could introduce Boron, why wouldn't they use that technique to grow blue rough....or introduce Nitrogen to grow yellow rough?

That's all being done. Here are some true-blue lab grown examples from Diamond DNA.

Click: 4.38 ct Fancy Intense Blue VS2 Half Moon Brilliant
Click: 6.00 ct Fancy Dark Blue SI1 Cut-Cornered Rectangular Mod Brilliant

Boron doping can be used for color origin in both HPHT and CVD output - type IIb, obviously - no post growth treatments needed.

They're producing other colors, as well.



Some colors only manifest with the application of post growth treatments. Not just HPHT, LPHT and annealing: Experimentation with irradiation is in fashion right now, among some of the front runners.

Here's a pretty amazing example of that: What was originally graded as a 10.06 carat carat HPHT-produced Fancy Intense Yellow Lab-Grown diamond came back to IGI for re-grading after its color was shifted to Fancy Vivid Pink through a dual process of irradiation and annealing.

 

[Alybetter]

Type II diamonds are rare in nature - about 2%. Most natural diamonds are type I.
Type IIA is the purest. Type IIB has a tiny bit of boron in the lattice and is blue and conducts electricity.
All (almost all) synthetic, man made or LGD's are type IIA.
Most small diamonds these days are made with HighPressureHighTemperature like superman style.
Most larger diamonds these days are made with ChemicalVapourDeposition in a methane gas chamber and laser microwaves

Thanks. I understand the different processes, but I struggled to find the differences between II and IIa online. Thank you for your explanation!
The two CVD IIa’s I have coming are just .30s. We shall see how they look.

 

[Garry H (Cut Nut)]

$16 Boron tester:

 

[Alybetter]

Hello @Alybetter .

Colorless CVD is reliably Type IIa, so it's identified that way on reports.

Colorless HPHT are widely Type IIa but, depending on process, can have slight traces of boron. To account for this, confirmation of Type II, without stipulating a or b, is the default for colorless HPHT on reports. Further analysis can be done to tease out a/b detail for any given HPHT specimen but involves added time & expense.

Side note: I suspect the HPHT grower who produced the most colorless output I've ever seen - it was nicknamed C color - was using trace amounts of boron. They wouldn't confirm, but that higher-than-D-color impression 'tasted' blue-white.

Thank you so much. Your explanation was helpful. I appreciate it.

 

[Rockdiamond]

Here's a pretty amazing example of that: What was originally graded as a 10.06 carat carat HPHT-produced Fancy Intense Yellow Lab-Grown diamond came back to IGI for re-grading after its color was shifted to Fancy Vivid Pink through a dual process of irradiation and annealing.

Interesting John. But I don’t see any sort of lab reports backing up the fact that the yellow diamond was as grown. Same for the blue ones. They really look just like irradiated diamonds. Which doesn’t mean they are irradiated…… but there’s not documentation indicating they are not. Nothing about boron either.

 

[DejaWiz]

Interesting John. But I don’t see any sort of lab reports backing up the fact that the yellow diamond was as grown. Same for the blue ones. They really look just like irradiated diamonds. Which doesn’t mean they are irradiated…… but there’s not documentation indicating they are not. Nothing about boron either.

This may not be new info, bit there is one tell-tale sign on some IGI reports that boron is present: it'll state HPHT and Blue Nuance.

These are typically found only with diamonds in the G or lower color grades, and not those categorized as fancy color.

 

[molecule]

annealing

@John Pollard Could you point me to any diamond annealing articles?

 

[Garry H (Cut Nut)]

@John Pollard Could you point me to any diamond annealing articles?

If you are really serious here is some material from an conference in France in 2019:
Read from about page 24 to page 39

https://static1.squarespace.com/static/5d820bb8a789f32f58d708c5/t/5d822682e84e2d149afe4605/1568810678087/IGC2019-web.pdf

 

[Rockdiamond]

This may not be new info, bit there is one tell-tale sign on some IGI reports that boron is present: it'll state HPHT and Blue Nuance.

Sorry to be a “doubting Thomas”…… but where does IGI definitively state Boron was introduced during growth?

 

[Garry H (Cut Nut)]

Sorry to be a “doubting Thomas”…… but where does IGI definitively state Boron was introduced during growth?

Hi David, I have enough science education to know I am about 50% right. I don't think boron can get in any other way than than in the original growth process.
Not even like this:

 

[Rockdiamond]

I don’t doubt that if boron exists in the lab grown diamonds, it was somehow added. But where are any definitive statements about boron being introduced during the growth process or that boron actually exists in lab grown diamonds ?
My understanding is that the blue lab grown diamonds on the market are irradiated.
Generally this would be done to rough that was not able to be grown colorless - the tint occurs if there are variations in the temperature during the growth process. ( as I understand it)
One grower we deal with has gotten so good at eliminating color in the rough, he needed to irradiate some D-E emeralds cuts to supply blue ones for an order.

I don't think boron can get in any other way than than in the original growth process.

 

[DejaWiz]

I don’t doubt that if boron exists in the lab grown diamonds, it was somehow added. But where are any definitive statements about boron being introduced during the growth process or that boron actually exists in lab grown diamonds ?
My understanding is that the blue lab grown diamonds on the market are irradiated.
Generally this would be done to rough that was not able to be grown colorless - the tint occurs if there are variations in the temperature during the growth process. ( as I understand it)
One grower we deal with has gotten so good at eliminating color in the rough, he needed to irradiate some D-E emeralds cuts to supply blue ones for an order.

Irradiation makes sense for forcing a color change post-growth, as in your example of the grower needing to supply some blue emerald cut LGDs

From what I understand, all blue "as-grown" lab diamonds are HPHT Type IIb because of boron being present, since I don't think that doping the gas phase with boron is cost-effective for attainment of fancy blue categorical diamonds with the current gem quality CVD process.
Boron doping in CVD is usually for industrial applications.

 

[John Pollard]

Dear doubting David,

Here you go.


Link to report: https://www.igi.org/viewpdf.php?r=LG12248513


Link to report: https://www.igi.org/viewpdf.php?r=LG12461501

 

[John Pollard]

Irradiation makes sense for forcing a color change post-growth, as in your example of the grower needing to supply from blue emerald cuts.

From what I understand, all blue "as-grown" lab diamonds are HPHT Type IIb because of boron being present, since I don't think that doping the gas phase with boron is cost-effective for attainment of fancy blue categorical diamonds with the current gem quality CVD process.

^ Just so. It can be done, but it's likely more practical to irradiate IIa CVD for blue results in jewelry applications.

And this may be obvious but I would state, for the record, HPHT produced IIa diamonds must be subjected to post-growth irradiation to cause blue. Only IIb have color origination as-grown.

 

[Rockdiamond]

Thanks John!
But….
1) that blue looks nothing like the initial blue diamonds you posted ( I’d be super interested to see more examples)
2) there’s no mention of boron or nitrogen

as a note: I’ve seen deep yellow lab growns. Lighter, non brassy yellows seem incredibly rare.

 

[Rockdiamond]

rom what I understand, all blue "as-grown" lab diamonds are HPHT Type IIb because of boron being present, since I don't think that doping the gas phase with boron is cost-effective for attainment of fancy blue categorical diamonds with the current gem quality CVD process.
Boron doping in CVD is usually for industrial applications.

Interesting!! What would be the industrial reason to add boron?
I’m still exploring the market….. but I don’t find a lot ( or any) blue lab growns with a report stating “as grown”
John posted one, so they apparently exist. Has anyone else seen more examples?

 

[DejaWiz]

Interesting!! What would be the industrial reason to add boron?
I’m still exploring the market….. but I don’t find a lot ( or any) blue lab growns with a report stating “as grown”
John posted one, so they apparently exist. Has anyone else seen more examples?

Diamond conductors.

All HPHT Faint Blue/Blue Nuance diamonds are "as grown" with trace amounts of boron present, whether the report specifically states it or not...there's no other way for that anomaly to occur with no post-growth treatment.

 

[Rockdiamond]

You’re using the term “Blue Nuance”….. is that a trade name?
I’m not seeing a lot of lab reports for blue lab diamonds stating “ as grown”
Also- I’m looking at larger, fancy shapes. Might be different than smaller stones.
If a lab grown diamond is blue, and not irradiated, wouldn’t the lab report notate that?
If it’s a reliable method ( introducing boron) why use irradiation at all?

 

[DejaWiz]

You’re using the term “Blue Nuance”….. is that a trade name?
I’m not seeing a lot of lab reports for blue lab diamonds stating “ as grown”
Also- I’m looking at larger, fancy shapes. Might be different than smaller stones.
If a lab grown diamond is blue, and not irradiated, wouldn’t the lab report notate that?
If it’s a reliable method ( introducing boron) why use irradiation at all?

Sorry, because I should have definitely clarified this earlier: Faint Blue or Blue Nuance nomenclature is found on non-fancy color LGDs.
They will be Type IIb due to the boron introduced during the HPHT growth process.

 

[John Pollard]

@Rockdiamond your question has been a moving target for me, so permit me to clarify.

You first stated:

Speculating here: If they could introduce Boron, why wouldn't they use that technique to grow blue rough

At the top of the thread, when you didn't know about boron doping, I presumed you might not be aware LGDs come in a variety of fancy colors (treatments notwithstanding). That's why I linked the various Diamond DNA examples.

Then:

My understanding is that the blue lab grown diamonds on the market are irradiated.

At that point I realized the question was "as-grown" specific. So I provided grading reports for a fancy deep yellow and fancy blue with no treatments. Question answered.

To be clear: Those reports were not related to the Diamond DNA examples. They were simply to help you understand that color origin can be as-grown, without treatment. With that said, the tech does exist to grow blues at high saturations as-grown, with no PGT.

As for this -

...where does IGI definitively state Boron was introduced during growth?

Where does anyone? If this was a reporting policy I suppose natural diamond grading reports would look something like this -

Shape: Heart Brilliant
Carat Weight: 0.50
Color Grade: Fancy Intense Pink
Clarity Grade: SI2
Comments: Graining not shown. Additional clouds not shown. Color originates from lattice distortions caused by intense heat and non-isotropic stress.

Actually, cool info. But not exactly romancing the aesthetic IMO.

 

[John Pollard]

Diamond conductors.

There's money to be made there. Circling back to process, my understanding is that CVD boron doping is somewhat impractical because it badly contaminates the chamber. Alternately, the most sophisticated HPHT producer I know reports that the majority of his capsules are producing deep or dark. Around 10% reaches vivid.

 

[Garry H (Cut Nut)]

Hi All,
Not sure what the big deal about type IIa lab grown is.
But seriously, you can test any diamond with a multi meter and if it passes a current or has a teeny bit of resistance then it has boron in the lattice.

 

[Rockdiamond]

At the top of the thread, when you didn't know about boron doping, I presumed you might not be aware LGDs come in a variety of fancy colors (treatments notwithstanding). That's why I linked the various Diamond DNA examples.

Please excuse my skepticism. I’m extremely well aware of the fancy colored LGDs John….as well as growers and dealers selling FCD lab growns.
I’ve seen thousands of carats at this point- and many blues and pinks. If there are non treated ones on the market, they are rare to be sure.
I still see nothing that indicates the Diamond DNA stones you liked to aren’t irradiated/ are there lab reports on those? Can you please post them?

About lab reports- given that LG lab reports commonly mention post growth treatments, it’s not unreasonable to expect them to identify Pre growth treatments.

Hi All,
Not sure what the big deal about type IIa lab grown is.
But seriously, you can test any diamond with a multi meter and if it passes a current or has a teeny bit of resistance then it has boron in the lattice.

To me, accurate info is crucial. And seemingly lacking in public discourse .
If procedures exist to use boron to create blue diamonds, where are the blue diamonds?


@DejaWiz
Curious- are you in the trade- or otherwise involved in diamond synthesis? You seem to know a lot about growing diamonds!

 

[aisa901]

If you've got some time on your hands, these GIA seminars go into extensive detail about all things lab grown diamonds.

The Evolution of Laboratory-Grown Diamond Evaluation at GIA | GIA Knowledge Sessions Webinar Series​

Starting at 33 minutes the speaker starts talking about color, then he explains how the lattice structure effects the color variations and type (IIa vs. IIb etc.) of the diamond, and then at 39:30 minutes, he says, "You can also add boron into the growth chamber, most commonly this is done in the HPHT diamonds, but the more boron you add, you go from something that still looks colourless with very tiny amounts of boron, but once you get over about 100 parts per billion boron, you start to get nice blue colors and then of course like with natural diamonds you can treat them by irradiation"... etc.

At about 40:00 minutes, he talks about color zoning, and how you can create a lab grown green diamond using a "color zoning" method.

There are also these videos:

Laboratory-Grown Diamonds: Updates and Identification | GIA Knowledge Sessions Webinar Series​

Laboratory-Grown Diamonds from China | GIA Knowledge Sessions Webinar Series​

 

[DejaWiz]

@DejaWiz
Curious- are you in the trade- or otherwise involved in diamond synthesis? You seem to know a lot about growing diamonds!

Nope...not trade or involved with synthesis.

I'm a EE educated field IT repair tech for a power generating company and a research geek that can't seem to get enough info crammed into my head.

Maybe someday I'll enter the trade (don't even know how to get started!) when my body calls it quits on the physical labor aspect of my career.

 

[oncrutchesrightnow]

Nope...not trade or involved with synthesis.

I'm a EE educated field IT repair tech for a power generating company and a research geek that can't seem to get enough info crammed into my head.

Maybe someday I'll enter the trade (don't even know how to get started!) when my body calls it quits on the physical labor aspect of my career.

Don’t know about you but science and engineering are part of the allure of LGD for me. Am curious whether in addition to the physical properties of LGD there has been much study on human perception. For example, is there categorical perception that draws a sharp line between blue nuance and fancy blue color? Anyway these technical discussions might not seem relevant for people outside the trade but a lot of us actually find them useful so.