Diamond tester recommendations

Hi,
I’m looking for a reliable diamond tester and have not found anything dependable that is currently available. Any suggestions, recommendations and warnings? Many thanks.
Jennifer

I’ve got a friend who owns a jewelry store who uses a diamond tester as an initial screening tool when jewelry comes in for repair. I’ll ask him what he uses tomorrow.

Have you reached out to jewelry tool companies who sell diamond testers? Otto Frei, Gesswein, Rio Grande, etc. They are know about the latest developments in various technologies.

Jeff

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I spoke to my friend who owns a jewelry store. He uses a Gemoro diamond tester that can identify diamonds, moissanite, and cz’s.

He likes it a lot and says that it’s easy to use.

I’ve spoken to the Gemoro folks at trade shows before. They seem to know their stuff. Most every jewelry tool company sells this tester.

Hope this helps!

Jeff

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Hey Jeff,
Thanks for sending that along. Let me say this with the caveat that my gemology training was a while ago…I do try to keep up, but let me know if I am wrong. $199 is not a lot to pay if it saves you from one mistaken ID mistaking a moissanite for a diamond. However, the old probes that separated CZ from diamond, but miss moissanite are much cheaper…maybe $20? Moissanite is very highly doubly refractive, so you ought to easily see doubled facets in some orientation. If I’m remembering right, the stone can be cut on the C-axis and then you won’t see any doubling looking directly down thru the table. However, you will see the doubling from other orientations. You will also see doubled rainbows refracted from the facets, whereas diamond will only show single rainbows…many people don’t know this little “visual optics” trick, but it is easy and foolproof. The late Dr. Hanneman used to say that the more gemology you knew, the fewer tools you needed, and this is an example of that. -royjohn

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Thanks royjohn! Great info. I’ll confess, I’ve never taken any gemology courses. There’s always been someone around in my career with those skills, so I’ve never taken the time.

As far as I know a diamond tester (like the Gemoro) is to give a rough idea of what a stone is. It’s not a certified test. To get certification of exactly what a stone is you need someone with the gemology skills you’re describing.

That said, diamond testers are very handy in certain situations. Like in the jewelry store that I went to. The owner is a jeweler and a gemologist, but not all of his employees are. The diamond tester is a great tool to give a rough idea what’s being taken in for a repair by a sales person.

Jennifer,
I hope this answers at least some of what you were looking for! Let us know if you have further questions.

Jeff

Yes, Jeff, I agree with you, these testers are convenient and make up for lack of gemology knowledge. I am just a crusty old geezer with an I-can-get-it-cheaper, I-can-do-it-better attitude. However, I can say that a lot of gemology techniques are very simple once you have read the books or seen the demo and know how they work. The store employee with the tester definitely needs a backup gemologist who can actually inspect the stone. -royjohn

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Thanks for the info Jeff and I agree that gemology training is ever useful. A diamond tester is also for a customer’s benefit, although no one wants to find out grandma’s rocks are look-alikes.
I’m a bit confused about the taking envelope reference. I’ve always labeled stones as clear and the color but never do I ever state that a stone is anything more than whatever color it is and the stone.
For example, a white or clear stone is what we write down, not a diamond. Because once you make that leap to the gem identification, you are beholden to it. If you state they dropped off a diamond then they must pick up a diamond even if what they dropped off is not a diamond.
I thought this was standard practice and am a bit confused.
Also, I only describe the characteristics: a yellow metal chain stamped 18 K, for instance is how I describe things. I’m very curious as to others approaches to this.

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That’s what I’ve been trained as well, to not label stones except white, clear stone, etc. But as the person working on the jewelry object and not being a gemologist, it’s helpful to know what the diamond tester says the stone is.

Yes, let’s see what others say are best professional practices.

Thanks Jennifer!

Jeff

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Also, I should probably add, how to label a job envelope is a different question from what’s the best diamond tester.

Correctly labeling a job envelope is a very big topic, because as you point out, it’s also about liability.

I’ll be honest, I’ve only done repair and custom work, when I have worked in jewelry stores. Except when talked into it for friends and family, I’ve been too afraid to take on that kind of work as a solo jewelry/artist. In my personal studio I only make new things, which is a very different perspective.

Jeff

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Hi Jennifer, Jeff and All,
Yes, Jennifer, that’s what I was also taught when I took the GIA gemologist course. You write “an untested 6mm round brilliant cut, colorless stone’” and you can add “described as a diamond by the customer” if you want, but perhaps that is going too far. -royjohn