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

This tester clearly displays hardness of all types of gems in all types of settings. It quickly clears up any mysteries about the gem at hand. Highly recommend!

This item pays for itself. It identifies counterfeit items. It identified a bunch of stuff from ebay and consignment stores.

This is my second Presidium gem tester. It is easy to use, although sometimes the calibration can be tricky. I have found that if you let the unit warm up for at least an hour, it minimizes the need for re-calibration. I use if for my vintage jewelry hobby.

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!

Bought this for my wife to use to check out all her jewelry. She discovered one piece is not a gem but colored glass! It took us a couple of times to calibrate it, but we did it successfully. Not sure what these kinds of things should cost, but it seems overpriced to me... but it's a supposed precision instrument so maybe it's not overpriced. It's certainly not industrial grade equipment, but good for the jewelry collector/reseller/buyer. Comes with a nice case. Seems to be more accurate and capable than the pens you can buy for a lot less money.

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.

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.

This is an easy to use tester. It is very accurate too. Easy to use. It was a little pricey but it all depends on if you want accuracy or not. I believe this is an accurate measure and trust worthy. b I recommend this item if you are testing gems.