Presidium Instruments Gem Tester II (PGT II) Now with Assisted Thermal Calibration (ATC) for Identifying Diamonds/Moissanites and Common Colored Gemstones

I am learning to use this gem tester, I purchase several vintage items and needed this instrument to confirm what the sellers of these jewelry items are wht they state they are. Further, I had to return the first unit as I did not think it was working properly nor did it have a user manual, and it looked used. Seller shipped via FED EX an exchange in record time, that to me was very impressive and showed that they care! Meanwhile I was able to download a user's guide and its been most helpful! Thank you 'FindingKing' for your excellet customer care, I appreciate you very much.

I was always wondering if the stones I buy were as described. This instrument helped with that deciding factor. I’ve had no issues with it so far.

I have only owned this tester for less than a month. So we'll see how things go over time. I haven't had any issues yet with the calibration (knocking wood). If you buy this, make sure to register your product right away so you can get assistance if your tester isn't performing as it should.I'm fairly inexperienced when it comes to gemstones, but I sell vintage jewelry (mostly costume) so I do come across items I need to identify from time to time. Honestly for someone like me, it's actually just great to be able to test older pieces and confirm whether I'm dealing with glass or a gemstone. I consider the tester to be a starting point for additional research, not necessarily the final word. I was pleasantly surprised to identify some pieces I own that I hadn't really assumed to be gemstones, or just didn't have a clue about the specific stone. But I can see the more likely scenario is that it will identify a stone as something like quartz, then I have to go do my research because that can encompass multiple varieties of stones. So if you consider this as a research tool and understand that you still have to go out and learn more information, this is a pretty good investment and will probably end up paying for itself.

Not well made. It worked reasonably well, although readings were somewhat inconsistent. It was a decent first screening tool. Then one day, after very limited use, the needle stopped moving. Almost $300 wasted! Buy something else!

It appears to work fine but it is overly costly.

This tester is amazing so glad I finally broke down and spent the money for it. It’s well worth it.

It worked as designed but you have different choices for gems and have to figure out which of those it is based on color. Since many gems can be different colors I couldn’t really figure it out. I know many people that use this tester and like it but it wasn’t for me.

I was hesitant, given the number of reviews that said their units were DOA and needed to be returned. However, I was to the point that I needed one to tell me what those dang stones were in that mountain of jewelry items that I wanted to sell. It arrived, we followed the calibration instructions and it has been working well since. I hope I didn't just jinx it. LOL A suggestion that my husband made, and it's very sound: start every session with a gem you are absolutely sure about, to make sure it's ready to go and reading accurately. I simply use the diamond in my engagement ring. I also go one step better, and retest the diamond a few times during the testing session, just to be sure we are still golden. I suspect having this device to verify gem identity will help make items sell for more & more often, and will pay for itself in a reasonable time. I'll update if there is more info. But so far, so good.