October 3-7—JOSHUA TREE, CALIFORNIA: Annual show; Sportsmans Club of Joshua Tree
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 Post subject: Problem with black diamonds
PostPosted: Thu Mar 08, 2018 4:33 pm 
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Hi!

This week I've received 2 black diamonds. I'm looking for the best prize in everything and I found (or they found me from an ad about Vicenza's show on my email) UNIGLO Diamonds from Antwerp. I asked for 2 diamonds of 1ct or more and they told me the prize... It sounds cheap (obviously because treatment) and I decided to buy them.

Yesterday I received it, so pretty I think. Everything looked wonderful (prize, quality, cut...) until I decided to check if they are diamonds with my tester (next one: Image)

To my surprise, it marks diamond but fastly marks moissanite... Anxiously, I take others black diamonds from my 'official' provider of diamonds and test them... Moissanite too... I don't know why because my 'official' provider never ever lied to me.

We've made other tests like specific weight (it was 3,49) and everything looks like diamond.

Could be a diamond and the test is wrong or has a problem? Could be a lab grown diamond although the company told me they are naturals? Could be because of irradiation they changed their characteristics and the tester works bad? Could be it has a tiny layer because of treatment and it can modify the test?

How could be a good way to determinate if they are natural diamond apart from sending it to a laboratory?

Strange thing is all of black diamonds I have (many time some of them) failed the test.

Can you help me?

Thank you!

PD: Sorry for my bad English.


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 Post subject: Re: Problem with black diamonds
PostPosted: Fri Mar 09, 2018 12:00 am 
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Black diamonds are often heavily included with dark inclusions and then irradiated to even out the color. I have heard of people getting different results on thermal testing with them, though this may reflect unreliable testers rather than a feature in the diamonds themselves. I don't know if the inclusions would affect the thermal conductivity enough to register (probably not??). The SG should at least remove black moissanite (sg 3.2~) as a possibility.


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 Post subject: Re: Problem with black diamonds
PostPosted: Fri Mar 09, 2018 10:29 pm 
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Hello.
Diamond/ Moissanite testers are VERY unreliable.
I find thermal diamond only testers better.

I have tested many black diamonds both natural and irradiated with success with a diamond thermal tester.

That being said, lots of black moissanite is being represented as diamond.
I don't think I would be searching for the cheapest price, but the most reliable seller.
Uniglo should be reliable

Black diamonds should be cheap. They are either heavily included like the ugly Orloff or irradiated unsaleable diamond dreck.

Sidebar: I think when you write "prize" you mean price.


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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 10, 2018 12:18 pm 
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Barbra Voltaire wrote:
Hello.
Diamond/ Moissanite testers are VERY unreliable.
I find thermal diamond only testers better.

I have tested many black diamonds both natural and irradiated with success with a diamond thermal tester.

That being said, lots of black moissanite is being represented as diamond. SG isn't moussonite so... what is happening? Could be it a lab-grown diamond?
I don't think I would be searching for the cheapest price, but the most reliable seller.


When you have too much competence and also sell to other jewelers, both parts (price and reliable seller are the best)

Uniglo should be reliable. Is there any way to know if they or others are realiable?

Black diamonds should be cheap. They are either heavily included like the ugly Orloff or irradiated unsaleable diamond dreck. What's mean 'dreck'?

Sidebar: I think when you write "prize" you mean price.
Yes, you're right! Sorry, I have a fixation for saying prize instead of price when I know they mean different. Sorry.


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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 10, 2018 1:04 pm 
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Dreck means rubbish, trash.

A synthetic lab grown diamond would be more expensive than natural or irradiated black diamonds.


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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 10, 2018 3:46 pm 
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Barbra Voltaire wrote:
Dreck means rubbish, trash.

A synthetic lab grown diamond would be more expensive than natural or irradiated black diamonds.


Ok! But I thing you're talking from the worst, isn't it? Not every irradiated diamond is unsaleable, isn't it?

So synthetic lab grown black diamond discarded (although I suppose you are talking about black diamonds because colorless diamond had fooled many people in big sizes... and those are a bit bigger than 1ct. On the other hand I've read natural black diamond without any treatment are rare and expensive).

About thermal tester... I tried it and it said 'diamond'... but the moussonite's one disagree with it.

Thank you.


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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 10, 2018 9:39 pm 
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I have that tester you have pictured. It is only a guide. Black diamonds commonly give a false reading in my experience. Use a microscope if you can. My unproven guess is that irradiated rough gives the wrong readings. Maybe someone can enlighten us.

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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 10, 2018 11:03 pm 
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Hi John. I have gotten incorrect readings with the diamond/moissanite testers with top quality diamonds.
If you want to buy an infallible tester, go with a GemmoRaman.

EstanisGM, no one would treat a diamond they believed would sell at a higher price if it was not treated. Once an unsalable diamond is treated, it hopefully becomes saleable. Treated black diamonds are actually a very dark brown, not black.

I do not believe anyone would manufacture synthetic blacks. Wouldn't be worth their time, nor the sophistication of the instrumentation required.


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 Post subject: Re: Problem with black diamonds
PostPosted: Sun Mar 11, 2018 3:08 pm 
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I have known one lot of black diamonds (very likely treated ones) to pick up a rhodium layer when a ring was sent off for plating. So they must have been conductive to electricity. As diamond/moissanite testers use electric conductivity to differentiate between the two (both being good conductors for heat), I imagine that would confuse the tester.

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 Post subject: Re: Problem with black diamonds
PostPosted: Sun Mar 11, 2018 6:42 pm 
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John, I have a microscope and it looks like black diamonds and also specific weight is 3,49... probably it's the tester but imagine if my customer goes to other jewelry and they check with similar tester and it signs 'moissanite'... It could be horrible!

Barbra, now I understand you with saleable and unsaleable you told me.

Keirkof, it could be a good explanation for setting ones but the one I bought is loose, not set yet.

The worst is my customer is waiting and asking everyday about diamonds... but I'm scared to sell them :(

I thing colorless diamonds are easier to check if they are natural... :(


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 Post subject: Re: Problem with black diamonds
PostPosted: Sun Mar 11, 2018 7:21 pm 
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Did you shine a light through, like a fiber optic. As I mentioned earlier black diamonds will actually appear brown around thee edges.


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 Post subject: Re: Problem with black diamonds
PostPosted: Tue Mar 13, 2018 9:15 am 
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Some diamonds will test moissanite on that tester. Type IIB comes to mind. Are you going to pass on selling those too? They are what they are inspite of the tester. If it is 99% accurate and you test 1000 diamonds you are going to have about ten problems. Get over the tester.

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 Post subject: Re: Problem with black diamonds
PostPosted: Fri Mar 30, 2018 10:54 am 
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Thank you for your answer...

And in this case, irradiation ones, how can I know if they stay on being radioactives or they lost their radiactivity?

I would like to know know about that because UNIGLO (again) offers me 4 tones of coloured diamonds (blue, brown, green and yellow) and they so pretty, but they told me because of small size (less than 2,4mm) they have to be irradiated. I asked about what kind of irradiation and they told me "by bombing them" but they can't tell me if it was bombing neutrons, electrons... so, how can I know that? I don't want to sell nothing dangerous for my customers. That's true it's not possible HPHT for this sizes?

i've heart about using 'bone scans' to check if they stay on being radioactives but I don't know how to get it without going to a doctor and pass a X-ray test.

Can you help me? I've attached a photo of them.

Thank you!


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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 31, 2018 9:16 am 
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I don't think you have to worry about any health risks unless you have an antique ring with one of the old green diamonds colored by radium salts. They would have been made about a hundred years ago. Modern technology leaves no residual problems.

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 Post subject: Re: Problem with black diamonds
PostPosted: Sat Mar 31, 2018 10:04 am 
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Can I correct the philology of "dreck"? It is a Yiddish word meaning "excrement". The rest of Barbra's opinions I cannot fault!


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