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Newbie Question: Difference between Natural and Lab grown?

JustMe111

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Hi,

I am very new to this type of products (diamonds) and wondering how could some expert with years or even decades of experiences see the difference, using whatever tools are needed, between Natural diamond and Lab grown diamond?

As far as I know experts also check and verify the structure in detail, particularly if some stranger would want to sell them something. But I don't understand if is possible, and how, to see the difference between natural and lab grown (i think called artificial or something like that).

Is it possible to sell lab grown as natural?

Thank you in advance.
 

John P

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Certain laboratory-grown diamonds can be identified by unique clarity features. And all of them grown in the normal color range fall into the Type IIa category. Only 2% of natural gem-quality diamonds are Type IIa so equipped experts are regularly using spectrometry to analyze diamond type, and sending anything falling under Type IIa for further analysis.

Is it possible to sell lab grown as natural?
Yes and no. In modern times most diamonds of value are always accompanied with grading documentation confirming natural origin. There's the chance that some bad actor could substitute a LGD for the real thing using this documentation, but it's unlikely that any established company would risk their reputation by doing this.

The largest area of question is melee (small diamonds sold without grading documentation). There has been good advancement in detection tech, but efficiency over tens of thousands of melee carats is problematic, and the solutions are so expensive that some stores and operations will be delayed or prevented from putting them in place. No one can predict the future but there is high likelihood that melee in general circulation will become increasingly salted with synthetics.

There's more discussion in this thread (this post is an overview of how LGD are produced).
https://www.pricescope.com/communit...e-diamond-industry-video.249301/#post-4557644

The original post in that thread links to a "State of the Diamond Industry" video from the Las Vegas show last month. Much ado about LGD.

There is also a specific forum on this site for LGD discussion.
https://www.pricescope.com/community/forums/laboratory-grown-diamonds-man-made-diamonds-mmd.60/
 

OoohShiny

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Hi,

I am very new to this type of products (diamonds) and wondering how could some expert with years or even decades of experiences see the difference, using whatever tools are needed, between Natural diamond and Lab grown diamond?

As far as I know experts also check and verify the structure in detail, particularly if some stranger would want to sell them something. But I don't understand if is possible, and how, to see the difference between natural and lab grown (i think called artificial or something like that).

Is it possible to sell lab grown as natural?

Thank you in advance.
Laboratory Grown Diamonds / Man Made Diamonds are chemically/physically identical to Mined diamonds, so no 'expert' could tell the difference without a laboratory machine, such as the grading labs use.

(The above assumes that there are no large, metallic inclusions that 'give away' their origin, of course.)

Actual differences tend to be fluorescence colours (if present, where orange is more common in MMDs and blue is more common in Mined) and the 'grain' of the diamond.

Also, in MMDs the 'grain' is flatter because it has been laid down gradually on sheets of diamond 'seed' material, whereas Mined diamonds are subject to massive pressures that twist and crush the structure of the stone (although some form quickly and might have more uniform structures, I believe). This 'grain' is effectively invisible without analysis using polarised light, I believe, so could not been seen with the naked eye.


Diamonds of a larger size should be graded by a grading laboratory to confirm their origin (i.e. GIA, AGS, IGI, AGSL) so you should not buy 'uncertified' diamonds in sizes over perhaps 0.2ct.

Under that size, there are indications that MMD stones are permeating the market and being sold as Mined stones. You should use a trusted vendor with a guaranteed supply chain to remove the risk of MMDs being sold as Mined stones, but even then, some may well slip through.



EDIT: I see John has replied while I was typing - he is much wiser and more knowledgeable than me so you should listen to him instead of me :)
 

Serg

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re: Laboratory Grown Diamonds / Man Made Diamonds are chemically/physically identical to Mined diamonds, so no 'expert' could tell the difference without a laboratory machine, such as the grading labs use.

Some comments about "physically identical"
CVD diamonds often have stria( RI variation) . It reduces fire and may be brilliancy . Such diamonds are less crispy. It is visible in direct spot light. It looks as bad facet polishing but problem comes from the material ( not from polishing quality ) .
See for example https://cutwise.com/diamond/38686
Screenshot 2019-06-12 18.15.29.png Screenshot 2019-06-12 18.15.35.png
 

Texas Leaguer

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re: Laboratory Grown Diamonds / Man Made Diamonds are chemically/physically identical to Mined diamonds, so no 'expert' could tell the difference without a laboratory machine, such as the grading labs use.

Some comments about "physically identical"
CVD diamonds often have stria( RI variation) . It reduces fire and may be brilliancy . Such diamonds are less crispy. It is visible in direct spot light. It looks as bad facet polishing but problem comes from the material ( not from polishing quality ) .
See for example https://cutwise.com/diamond/38686
Screenshot 2019-06-12 18.15.29.png Screenshot 2019-06-12 18.15.35.png
Interesting. Do HPHT synthetics have any problems of this nature?
 

Karl_K

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The largest area of question is melee (small diamonds sold without grading documentation). There has been good advancement in detection tech, but efficiency over tens of thousands of melee carats is problematic, and the solutions are so expensive that some stores and operations will be delayed or prevented from putting them in place. No one can predict the future but there is high likelihood that melee in general circulation will become increasingly salted with synthetics.
I think it will get to the point that no one will care with melee.
The cost of melee is in the handling and the cutting so there is no real cost advantage either way on the consumer level.
 

Texas Leaguer

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I think it will get to the point that no one will care with melee.
The cost of melee is in the handling and the cutting so there is no real cost advantage either way on the consumer level.
I tend to agree. Accent diamonds will be viewed as a component of the jewelry. And distinct from the center stone.

Most people will continue to want certified natural center stones for their rarity, stored value, and Earth born provenance.
 

John P

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Interesting. Do HPHT synthetics have any problems of this nature?
No. Stria in CVD is a by-product of the growing process. Think of carbon rain falling onto a substrate, growing vertically in parallel layers.

HPHT can have some peculiar characteristics tho. Since a metal catalyst is used some clarity characteristics take on a metallic appearance. Also, after superheating, the diamond material can retract and pull away from an inclusion/fragment during the cooling process, leaving a void with an identifiable look. This is absolutely man-made, a clarity characteristic found nowhere in nature. I think the grading laboratories missed a chance to do something groundbreaking and create a new name for such man-made fragment/voids. Instead they call them crystals in most cases.
 

John P

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I tend to agree. Accent diamonds will be viewed as a component of the jewelry. And distinct from the center stone.

Most people will continue to want certified natural center stones for their rarity, stored value, and Earth born provenance.
I'm with you and @Karl_K. I'd leave room for niche demand, though. If there's a large enough audience for "100% natural" finished jewelry there are high street stores and brands capable of sourcing and delivering natural melee in closed channels.
 

Texas Leaguer

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I'm with you and @Karl_K. I'd leave room for niche demand, though. If there's a large enough audience for "100% natural" finished jewelry there are high street stores and brands capable of sourcing and delivering natural melee in closed channels.
Absolutely there will be those who will settle for nothing short of 100% natural. Especially for their engagement/wedding rings.
 

OoohShiny

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I respectfully disagree. Your posts are tremendously informative and helpful @OoohShiny . You keep doing you. ;-)
You are far too kind, good sir :)


No. Stria in CVD is a by-product of the growing process. Think of carbon rain falling onto a substrate, growing vertically in parallel layers.
Is it the case that carbon is injected / vaporised in stages, meaning the layers' growth is controlled to an extent?

Or is it a case that the seed crystal sits in a dense cloud that gradually bonds to the seed, until all the airborne carbon is now attached? (with the amount of carbon cloud present depending on the depth of the crystal needing to be grown?)

I guess I'm wondering if the layering effect would/could be reduced by a tweaking to the manufacturing process! (although I'm sure such things have already been thought of... lol)

I have seen some MMDs with what looks like a lot of streaks across the facets, but I'm not sure if that was just poorly finished cutting/polishing or if it was a property of the crystal!


HPHT can have some peculiar characteristics tho. Since a metal catalyst is used some clarity characteristics take on a metallic appearance. Also, after superheating, the diamond material can retract and pull away from an inclusion/fragment during the cooling process, leaving a void with an identifiable look. This is absolutely man-made, a clarity characteristic found nowhere in nature. I think the grading laboratories missed a chance to do something groundbreaking and create a new name for such man-made fragment/voids. Instead they call them crystals in most cases.
Surely 'cavity' would be more appropriate, assuming they are not going to create a new category?!
 

OoohShiny

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CVD diamonds often have stria( RI variation) . It reduces fire and may be brilliancy . Such diamonds are less crispy. It is visible in direct spot light. It looks as bad facet polishing but problem comes from the material ( not from polishing quality ) .
See for example https://cutwise.com/diamond/38686
Screenshot 2019-06-12 18.15.29.png Screenshot 2019-06-12 18.15.35.png
Would this be a good example of a stone with obvious stria?

https://www.jamesallen.com/loose-diamonds/emerald-cut/0.62-carat-g-color-vs2-clarity-sku-7011880

It looks like poor polishing, and it only has VG polish on the grading, but it also looks internal??
 

Serg

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OoohShiny

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Thanks, Serg! :)
 

Karl_K

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CVD is in some ways like spraying paint with a spray can.
You spray back and forth building up thin layers until you get the thickness you want.
You cut it in half across the top and look at both sides of the cut, in an ideal world all you would see is a glob of paint. In the real world you will see layer lines some more obvious than others. The ones that went down perfectly will be very tiny to none but some where everything was not perfect will leave eye visible lines where there are different layers.
The holy grail of cvd is no to super small layer lines and some processes will do it better than others.
I am guessing that balancing growth speed vs quality is an issue.
 

Karl_K

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@Karl_K Thank you for that analogy. What analogy could be used for the growth of mined diamonds?
Hmm not sure.
It would be similar to how hthp diamonds grow. High Temperature High Pressure
Under very high heat and pressure when the right materials are present they grow like other crystals.
They are then brought to the surface by volcanic pipes.
 

OoohShiny

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Just to add to this thread, @kgizo was kind enough to highlight in the Lab Grown section of the forum that HPD have a great selection of photos of the potential inclusions found within MMD that are not found within Mined stones, as referenced earlier by @John Pollard:
https://www.pricescope.com/community/threads/unique-characteristics-in-mmd.250194/

Thanks to @Wink for hosting such useful info! :))


I was thinking earlier (always a dangerous thing ;-) :lol: ) re: the comments in this thread regarding CVD layering / striation - have there been any empirical analyses done on its impact on fire / brilliance / 'crispness' yet?

Or is it the case that 'the industry' have noticed its impacts and its being discussed, but GIA (for example) haven't yet done any research?

Or... is it one of those 'unquantifiable' things, similar to the things that Serg is working hard to quantify in his ongoing work?!
 

Karl_K

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Just to add to this thread, @kgizo was kind enough to highlight in the Lab Grown section of the forum that HPD have a great selection of photos of the potential inclusions found within MMD that are not found within Mined stones, as referenced earlier by @John Pollard:
https://www.pricescope.com/community/threads/unique-characteristics-in-mmd.250194/

Thanks to @Wink for hosting such useful info! :))


I was thinking earlier (always a dangerous thing ;-) :lol: ) re: the comments in this thread regarding CVD layering / striation - have there been any empirical analyses done on its impact on fire / brilliance / 'crispness' yet?

Or is it the case that 'the industry' have noticed its impacts and its being discussed, but GIA (for example) haven't yet done any research?

Or... is it one of those 'unquantifiable' things, similar to the things that Serg is working hard to quantify in his ongoing work?!
It has been noticed its also the reason many cvd diamonds are finished using hpht to drive off the color and drive off some of the crystal defects to get white diamonds.The same thing is done with hpht treated mined diamonds.
While not a perfect parallel, think of that paint glob above now put it into a heated press and press it together to get a more uniform bit of paint when you cut it in half and look at the cut edges.
 

Lessics

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So if one want's to buy a lab diamond isbthe HPHT diamond a better choice? Are they more expensive?
 

OoohShiny

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So if one want's to buy a lab diamond isbthe HPHT diamond a better choice? Are they more expensive?
Pricing is still all over the place, lol.

I am hoping that PS might have a MMD listings search tool at some point, as comparability across the market would make purchasing a lot easier and also show disparity of pricing between vendors, which should in theory drive more consistent pricing in the market.

(And hopefully that pricing will be consistently lower rather than vendors thinking they can increase their prices to match the most expensive vendors... lol)


As for CVD vs HPHT... some CVD are HPHT treated to improve colour and reduce layering/stria, as Karl has mentioned, so it's not necessarily a case of only one or the other!

Lightbox stones are CVD but they seem to have no issues in terms of brown/pink tint or stria - but they limit them to 1ct max (and those 1ct are like rocking horse poo... lol).
 

Ibrakeforpossums

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"Rocking horse poo" - what at great analogy! At least with real horse poo you get . . . hay in your hair.
Seriously, you've seen them and noted what?
 

OoohShiny

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"Rocking horse poo" - what at great analogy! At least with real horse poo you get . . . hay in your hair.
Seriously, you've seen them and noted what?
To ensure total clarity, I must declare that I have not seen any of the MMDs in person yet - my knowledge base is formed from the information and pictures posted on here and things like the GIA research document/articles.

Is there anything in particular you are seeking more information on?
 

lovedogs

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Also haven't seen in person, but the lightbox ones don't look well cut at all. I've seen well cut ones from brilliant earth (when you can check the certificates), and from @Rhino at August vintage. But I wouldn't buy any from lightbox unless I didn't care about cut
 

Garry H (Cut Nut)

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Just saw this old thread.
The cause of Internal Graining in CVD is very likely the same as I G in natural diamonds - interruptions in growth.
When there is a power interruption during the 2-4 week growth process, just as when the supply of carbon or growing conditions change in natural diamonds, there is a new growth begun and some stuff that is not quite right on the growth surfaces.
In natural diamonds this tends to be more common in maccles which are twinned triangular outline shapes, and sometimes the orientation of the triangular (octahedral) faces reorient as in this image:
1604902257710.png

In the case of a CVD diamond, as I understand, best practice is to remove the diamond that has been interrupted during growth and polish the surface before regrowing more diamond. But of course that adds to the cost. I do not believe the growers are the polishers - they are selling their rough.
Clearly having no power loss is critical, but since most diamonds are grown in India and China, the power supply is not always reliable.
 
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