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Internal Graining Comparison

CBPearllover

Rough_Rock
Joined
Feb 19, 2019
Messages
56
I was so happy he posted this video on IG! It answered many questions I had regarding stria and clarity issues. I've poured through MMD inventory through a few vendors, and I've always wondered if what I see on the videos would show in real life (pinpoint stria and that hazy/film-like glaze that looks like bad polish). Makes me feel way better about sending my future SIL to Distinctive Gem for a MMD, thanks @Rhino!
 

Rhino

Ideal_Rock
Trade
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Mar 28, 2001
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6,278
I was so happy he posted this video on IG! It answered many questions I had regarding stria and clarity issues. I've poured through MMD inventory through a few vendors, and I've always wondered if what I see on the videos would show in real life (pinpoint stria and that hazy/film-like glaze that looks like bad polish). Makes me feel way better about sending my future SIL to Distinctive Gem for a MMD, thanks @Rhino!

thank you kindly. Yes ... it's something I've seen in them from day 1 with it being both visible and invisible to the eyes. Anything that would alter the transmission positive or negative is something I like to be aware of as well as for my clients.
 

OoohShiny

Ideal_Rock
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8,221
Please provide me your email address?thanks

If you click on the website address in his signature, you should be able to contact him off his site.
 

Annahew

Rough_Rock
Joined
Jan 16, 2020
Messages
2
Is this due to the material, or is it because of the polish? Would a repolish fix the issue?
 

OoohShiny

Ideal_Rock
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Is this due to the material, or is it because of the polish? Would a repolish fix the issue?
Stria are (is??) internal graining due to the way the material is laid down in layers in Chemical Vapour Deposition (CVD) diamonds.

I found this thread useful in discussing various aspects of it:

 

Annahew

Rough_Rock
Joined
Jan 16, 2020
Messages
2
@OoohShiny interesting read, thank you for the link! I’m now wondering, if all lab diamonds with stria will have less fire, or only some, or will it be a scale?
 

OoohShiny

Ideal_Rock
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8,221
@OoohShiny interesting read, thank you for the link! I’m now wondering, if all lab diamonds with stria will have less fire, or only some, or will it be a scale?

I'm honestly not sure - I will have to defer to experts on that front!

I know @John Pollard has previously written about stria (amongst other aspects of MMDs), with the article on the High Performance Diamonds website, IIRC.

@Serg's Cutwise platform quantifies Fire for the diamonds listed, but I don't know if two (hypothetical) identically-cut stones, one CVD MMD and one Mined, would show identical Fire??
 

John P

Ideal_Rock
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Thanks for the tag @OoohShiny

@OoohShiny interesting read, thank you for the link! I’m now wondering, if all lab diamonds with stria will have less fire, or only some, or will it be a scale?
It varies.

From a prior discussion - As more players enter the game it’s inevitable that human-produced synthetic rough output becomes more variable. This is exaggerated by entities who are entering the fray with less resource, lower quality equipment, presses converted from industrial use to GQ, contamination confounders, etc.

My personal experience? The polished laboratory-grown diamonds I’ve seen with muted performance qualities were exclusively HPHT annealed CVD output. The samples were all similar: A casual gemologist might consider the deficits as surface-polish issues. It’s worth noting that CVD is far more challenging in cross-working and brillianteering than HPHT rough. Honestly, its a PITA to cut. So polish challenges do come into play. But there is a direction and depth to the visual muting (the term muddying is also used - not my word) which goes deeper than surface polish.

Full post and context here.

... lab diamonds with stria ...

Just a note that natural and laboratory-grown diamonds produced using the HPHT-process grow differently than CVD. The influence from stria is a by-product of CVD's vertical growth.



"CVD rough material. Courtesy SoniCVD"


"A cloud of black inclusions on a single plane shows the layered growth and stop-start cycles of CVD synthesis."

More photos can be found here.

I'm convinced that visual muting occurs when (a) equipment-quality isn't superior and/or (b) the growth timeline is rushed.

If you examine the output from a top producer who doesn't rush all may be fine, compared to fly by night operations that have surfaced in China, more focused on spamming your inboxes than refining their output.
 

OoohShiny

Ideal_Rock
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Thank you, kind sir! :))
 

MelloYello8

Shiny_Rock
Joined
Jul 6, 2018
Messages
318
Thanks for the tag @OoohShiny

If you examine the output from a top producer who doesn't rush all may be fine, compared to fly by night operations that have surfaced in China, more focused on spamming your inboxes than refining their output.
This is interesting because with the sudden spike in stores selling lab diamonds, I think some of the aspects that drew me to them are diminished, particularly ethical and ecological concerns. For those who are solely drawn by the price, more competition pulling prices down can’t be a bad thing. I’m not in the market for any diamonds now but the laser inscriptions and/or IGI certs that note the diamond is made in the USA would be more important to me next time I shop. Now it seems it would be not just for the ethical standards but perhaps the quality too.
 
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Eeveepenny

Shiny_Rock
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Jun 11, 2020
Messages
202
How would one screen for Stria/internal graining when searching for a MMD with only a 360 video available? Is it easy to see, what would a deal breaker amount of Stria look like?
Is this Stria? And is it bad enough that it would affect the light performance and overall look of the diamond?
6D1B7D77-AFF4-4F0A-B925-2CF87A72B079.jpeg
 

Attachments

OoohShiny

Ideal_Rock
Premium
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Apr 25, 2014
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8,221
In addition to my above post. This is a video of the diamond
In my (non expert!) opinion, I think that has a touch of stria showing, but don't forget it is massively larger on screen than in real life.

I don't think there has yet been any studies / quantification of whether stria impacts light return, and if so, to what extent, but I would be interested to find out.


If you are considering the diamond listed, make sure the Returns policies would allow you to return it if you are not happy.
 

Lessics

Brilliant_Rock
Joined
Jan 6, 2019
Messages
689
Imo this isn't quality lab diamomd material for me it would be too much striation. .I also find diamond foundrys prices crazy.
 

Rhino

Ideal_Rock
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6,278
As I've been studying this rather intently and have purchased lab equipment that helps me not only in it's detection but degree upon which it can impact transparency and light return, I'll tell you that 360's and the still images they produce are not reliable for determining whether it'll impact it in real life or not. There are definite graining patterns to observe under microscopic examination that help to easily weed em out. There are no flags, positive or negative upon which to make that judgement call.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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.I also find diamond foundrys prices crazy.

The price problem is that companies are pricing man made diamonds off the natural rarity of natural diamonds.
For example a D VVS 2ct lab grown diamond costs more than a F VS diamond.

Given these are manufactured products they should be made to a standard based on what consumers expect.
OK, there could be Ferrari and Kia versions with different companies offering different minimum qualities. But applying a rarity basis to selling prices is not relevant IMO.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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As I've been studying this rather intently and have purchased lab equipment that helps me not only in it's detection but degree upon which it can impact transparency and light return, I'll tell you that 360's and the still images they produce are not reliable for determining whether it'll impact it in real life or not. There are definite graining patterns to observe under microscopic examination that help to easily weed em out. There are no flags, positive or negative upon which to make that judgement call.
I agree Rhino - lighting and viewing directions make it very hit and miss with the chance of lining up with the grain direction.
Again - we are using technologies developed for natural diamonds - and not ones specific to this product.
 

Eeveepenny

Shiny_Rock
Joined
Jun 11, 2020
Messages
202
Imo this isn't quality lab diamomd material for me it would be too much striation. .I also find diamond foundrys prices crazy.

Imo this isn't quality lab diamomd material for me it would be too much striation. .I also find diamond foundrys prices crazy.

I ended up switching to another diamond which doesn’t show any Stria in the video. But I will wait until I get the diamond before I get too excited. The diamond I bought is a foundry diamond but it was from another supplier and it was significantly cheaper than the price listed on the foundry website. Pays to shop around imo
 
Last edited:

Garry H (Cut Nut)

Super_Ideal_Rock
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15,968
Question - are stria only as a result of interruptions and restarting the carbon rain?
1. If the tablet was removed and re polished back to perfectly smooth - would that remove the problem and make the stone have high transparency?
2. are the interruptions a result of power being cut off in 3rd world countries?
3. is it possible the stria are always present at a higher microscopic scale?
4. when will labs begin measuring and reporting transparency (and not disguising it in jargon under clarity?).

Finally - the big question - sshhhhaaaTrom!

Why call it stria and not call it internal graining?
 

MelloYello8

Shiny_Rock
Joined
Jul 6, 2018
Messages
318
While it seems CVD diamonds represent most lab diamonds these days, I wonder if there are colorless HPHT diamonds still being made (and improved) that wouldn’t have the stria concerns.

The distinction could be akin to the synthetic gemstone market with cheaper flame fusion that also exhibits stria vs pricier hydrothermal growth.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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Growing large HPHT is not viable.
Double the polished weight with CVD takes way less than double the run time.
It seems pretty clear De Beers have the upper hand with know how and patents and no one is game to steal their IP. I think De Beers have that as part of their strategy. Try and we will bankrupt you!
Its fun to watch
 

Lessics

Brilliant_Rock
Joined
Jan 6, 2019
Messages
689
Growing large HPHT is not viable.
Double the polished weight with CVD takes way less than double the run time.
It seems pretty clear De Beers have the upper hand with know how and patents and no one is game to steal their IP. I think De Beers have that as part of their strategy. Try and we will bankrupt you!
Its fun to watch


Do you mean growing larger HPHT Stones is not viable? Like 200 carat or are you talking about 10 carat?
 

MelloYello8

Shiny_Rock
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Jul 6, 2018
Messages
318
It seems that 1-2 carats is the sweet spot for e-rings. If for argument sake a certified CVD rock averages $1,000 for one carat and takes 3 weeks to grow, and a similar natural diamond is $3,000. If it takes 6 weeks to grow HPHT, they can fill that niche market that is willing to pay more than $1,000 to avoid stria - say $1,500 to $2,000- but still seek to save money (or go lab for ethical reasons). Would this not be profitable for HPHT growers?
 

Garry H (Cut Nut)

Super_Ideal_Rock
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Do you mean growing larger HPHT Stones is not viable? Like 200 carat or are you talking about 10 carat?

Larger diamonds cost 3 to 4 times more to grow using HPHT.
Smaller diamonds cost 10 times more to grow using CVD.
 
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