CVD diamond detection for the cost of a pair of sunglasses

[Garry H (Cut Nut)]

From a discussion at https://www.pricescope.com/communit...rst-real-threat.175721/#post-3210744#p3210744

On a Linked in discussion my friend Branko - he mentioned a simple method for identifying CVD (and HPHT) small diamonds in parcels that would never go to labs because of size/volume/cost.

It turns out that because CVD diamonds are grown on flat bases of an existing diamond, layer upon layer, that they tend to have vertical columns of stress which, as all diamond gemologists know, stress in singly refractive gems can be seen between crossed polarizing filters. e.g. if you broke a pair of polaroid sun glasses in half, placed the diamond on one lens and turned the other lens at 90 degrees and looked with a loupe or microscope you will see the strain.

Polariscope is one of the least expensive and most common gem tools that is in the 101 lesson - https://www.google.com/search?tbm=isch&hl=en&source=hp&biw=1366&bih=643&q=polariscope&gbv=2&oq=polariscope&aq=f&aqi=g1g-S9&aql=&gs_l=img.12..0j0i24l9.1269.3381.0.6245.11.10.0.1.1.0.116.1020.1j9.10.0...0.0.DBdsS97LTGg

So thanks to our wonderful scientificly trained Gemologists, there is no reason fakers can get away with cheating.

Acknowledgement: Branko Deljanin (Canadian Gemological Lab, Vancouver ) and Dusan Simic (Analytical Gemology and Jewelery, New York).

 

[Paul-Antwerp]

Re: CVD diamond detection for the cost of a pair of sunglass

Thank you for sharing this, Garry, but may I add a few words of caution.

In theory, this method might prove to be an indicator of the diamond being CVD-grown. I doubt that this method will work on HPHT-treated stones, but it could be that your choice of words in that respect was just unlucky.

On the flipside however, we should add that we do not have an indication yet that this detection-method has been thoroughly tested, and confirmed by independent verification. And in that respect, we probably need to caution at the same time that false-positives are possible, because it might be rather difficult to discern between stress as such (occurring in natural diamonds) and vertically columned stress.

Live long,

 

[Garry H (Cut Nut)]

Re: CVD diamond detection for the cost of a pair of sunglass

Thank you for sharing this, Garry, but may I add a few words of caution.

In theory, this method might prove to be an indicator of the diamond being CVD-grown. I doubt that this method will work on HPHT-treated stones, but it could be that your choice of words in that respect was just unlucky.

On the flipside however, we should add that we do not have an indication yet that this detection-method has been thoroughly tested, and confirmed by independent verification. And in that respect, we probably need to caution at the same time that false-positives are possible, because it might be rather difficult to discern between stress as such (occurring in natural diamonds) and vertically columned stress.

Live long,

Paul Branko has identified a different pattern for HPHT diamonds.
In the case of small diamonds which we always trade in parcels it seems that identifying this feature is common enough to be a safe positive of "dont deal with this vendor" and send the parcel to a lab if you can.
Branko has run tutorials for GemA in the UK.

 

[Paul-Antwerp]

Re: CVD diamond detection for the cost of a pair of sunglass

Garry, I have great respect for Branko in this, but I have a problem with your choice of words.

You seem to be depicting this ID-method as simple and fool-proof. After you explaining this to us in Vegas, I have tested it out on dozens of 100% natural, untreated diamonds of various sizes.

Not only does the procedure become more difficult as diamonds get smaller, I also had serious doubts in about 10% of the stones, since I could not possibly make a difference between the stress being vertically organized or not. As such, I found the method very interesting, but definitely not simple and proof enough for this fool.

Live long,

 

[Garry H (Cut Nut)]

Re: CVD diamond detection for the cost of a pair of sunglass

Garry, I have great respect for Branko in this, but I have a problem with your choice of words.

You seem to be depicting this ID-method as simple and fool-proof. After you explaining this to us in Vegas, I have tested it out on dozens of 100% natural, untreated diamonds of various sizes.

Not only does the procedure become more difficult as diamonds get smaller, I also had serious doubts in about 10% of the stones, since I could not possibly make a difference between the stress being vertically organized or not. As such, I found the method very interesting, but definitely not simple and proof enough for this fool.

Live long,

Thanks Paul, do you have access to any CVD diamonds to see a comparison?
(I hope the 10% in your sample are not CVD's hahahaha)

 

[Paul-Antwerp]

Re: CVD diamond detection for the cost of a pair of sunglass

The 10% were confirmed natural and untreated independently, Garry.

I do not have access to CVD-diamonds, and that is precisely my point. The majority of the trade does not have access or experience with CVD-diamonds, and if one has to first build up experience with CVD to use this detection-method, that should be clearly presented.

Live long,

 

[Garry H (Cut Nut)]

Re: CVD diamond detection for the cost of a pair of sunglass

Paul like all new developments in ID they require training.
the fact that this is all that is required is good.
I am trying to have Branko visit Australia and run courses as he has in the UK

He has specimens for training

 

[Garry H (Cut Nut)]

Re: CVD diamond detection for the cost of a pair of sunglass

Paul like all new developments in ID they require training.
If indeed we all have the tools and just need the training then this is good.
I am trying to have Branko visit Australia and run courses as he has in the UK.
He has specimens for training purposes.

 

[Karl_K]

Re: CVD diamond detection for the cost of a pair of sunglass

hmm since the stones are small, add magnification to increase the accuracy of the test and or a camera system to put it on a computer screen.
Interesting development.
I wonder if pattern matching software could be used to automate the process.

 

[Paul-Antwerp]

Re: CVD diamond detection for the cost of a pair of sunglass

Wow, we go back in time.

And I must admit, I had totally forgotten about this exchange.

Garry, do you have any further news here? We are four years later, and I have not heard anymore about this technique.

I do see labs creating a lot of upheaval about potential mixing of very small CVD in parcels of natural diamonds, at the same time promoting screening-services bringing them extra revenue. That screening is still based upon Type-IIA-detection, and refers a percentage of natural diamonds to further testing.

What did further testing of the Branko-technique deliver as results?

Live long,

 

[Garry H (Cut Nut)]

Re: CVD diamond detection for the cost of a pair of sunglass

Wow, we go back in time.

And I must admit, I had totally forgotten about this exchange.

Garry, do you have any further news here? We are four years later, and I have not heard anymore about this technique.

I do see labs creating a lot of upheaval about potential mixing of very small CVD in parcels of natural diamonds, at the same time promoting screening-services bringing them extra revenue. That screening is still based upon Type-IIA-detection, and refers a percentage of natural diamonds to further testing.

What did further testing of the Branko-technique deliver as results?

Live long,

The fact you and I never got one indicates it was marketing hype Paul

 

[Paul-Antwerp]

Re: CVD diamond detection for the cost of a pair of sunglass

Hi Garry,

I am sorry, but I am curious about your cryptic reply.

Are you saying the 'scary industry-reports' about CVD-mixing is marketing-hype, or are you referring to the Branko-detection-technique?

Live long,

 

[Garry H (Cut Nut)]

Re: CVD diamond detection for the cost of a pair of sunglass

Oops, my bad Paul - I thought it was a discussion about a device launched at HK trade fair a few years back that went no where.

Branko's approach is great for ordinary trade folk like us - but still often requires a stone needing to be sent to a lab with serious tools.
He is about to launch an origin report for pink diamonds in conjunction with the big gem lab GRS. They have also been running very successful Mediterranean gem conferences. Next one is in Syracuse - lovely part of the world!