StillCool Diamond Tester, High Accuracy Diamond Tester Pen, Diamond Tester Professional, Diamond Detector Gem Tester Gemstone Gemstone Tester, Black

I liked that it did let me separate my wife's jewelry stash into diamond and not diamond piles. She passed away a year ago without us ever going over her jewelry so that I would what was what. The device is a little awkward to use since you must be touching the jewelry with one hand and holding the tool in the other. If you are going to test small diamonds in their settings I suggest you use a loupe so you can more easily get the probe onto the stone itself. Since you are measuring heat transfer you really must have the probe perpendicular to the diamond to insure the heat is properly transferring. And, you must insure the stones are clean since a film of dirt and oil can impede the heat transfer and lead to an incorrect reading.

1 Don't believe reviews that say this item does not work. It works perfect for me.2 Tested Diamond, Moissanite, Ruby, Tanzanite, Topaz, London Blue Topaz and Cubic Zirconia. All the readings were perfect.3 Set at 4. Diamond and Mossanite blew red, other precious stones 6 or 7. Cubic Zirconia did not move.4 I don’t have an expensive machine to compare this to, but for me it identified all the stones I tried it on.5 Make sure your fingers are on the metal plate.6 IMPORTANT Diamond ( hardness 10) and Moissanite ( Hardness 9.5) tested the same. So don’t use this to validate authenticity.7 Yes, I recommend it and would purchase it again.

I received a few days ago and put it through some tests. I have some (quite a lot) of antique rings, most with stones that I wanted to check... honestly, I wanted to get an idea of which were garnets and which were rubies. Turned it on and waited for it to warm up, looked at the back to see what the calibration rates were and to calculate C to F. It's much easier to test jewelry with the tester by holding it in your hand, and make sure to keep a finger on the metal pad on the back. I found that with diamonds the testing was the quickest, the bars just shot right up the tool; testing other stones took a little bit longer for me as sometimes there was a pause before an extra bar showed up.I tested diamond chips and various sizes ranging from .05 to a .25c old European cut , everyone tested as a diamond... I have one piece of paste on a pin that I also tested, no movement whatsoever. Another thing I noticed was that it didn't matter if I had the calibration set for a larger stone (2 bars) when I tested diamonds, they shot all the way up regardless. It does matter if you are testing gems that aren't diamonds though.After that I moved on to the sapphires, I have white/blue synthetics, a couple of star sapphires, a natural white and a 1ct blue... all tested with 4 bars added to the calibration (not sure what would have happened if I had a really small one though and used the 8 bar to begin with). I also tested a stone that I thought was glass that I had on a great looking 10k ring. This stone was really dull and ugly, and around 1/3c... calibrated the tool at 4 bars and to my amazement it went up 4 bars. After soaking the ring in a glass of warm soapy water and then cleaning it with a toothbrush, I was excited to see how much it sparkled, no fire but certainly a beautiful stone and comparable to my natural white sapphire.I also tested a few loose small stones I have and found that it was almost easier to test them while holding rather than using the stone holder.On to the rest of what I found: When testing , Rubies +4, Sapphires +4, Amethyst +2, Emeralds & Garnets +1 (Members of the Beryl family have a very wide range of conductivity, so your results could be different depending on origin) Opal +0, {onyx, tigereye, agate, bloodstone, carnelian, moonstone} +1, Hematite +2. I also found one or two stones that I still can't identify but definitely narrowed down what they might be, found out that the purple stones in a turn of the century carved gypsy setting were pyrope garnets rather than the amethysts I thought and realized that two of the lower end rings I thought had glass/paste actually had gems on the lower end of the range.I will also add that just as this diamond/gem tester won't differentiate between mined diamonds and lab-created diamonds, it gives the same +4 on the mined rubies in my Edwardian jewelry as the synthetic ruby of a 1950's ring. All in all I like it a lot, although it can be a bit cumbersome at times. The cap fits on it well and keeps the tip protected along with the case.Just keep an eye on where the bars are after each test because sometimes you may have to adjust it back down a tad. I was usually testing the non-diamond gemstones a couple of times due to a slower bar time. I'll update further on the longevity.

It’s been hit and miss. If you let it touch anything metal it will go off like diamond. Meaning it’s tricky to test smaller diamonds as it’s incredibly difficult not to touch the settings. Though I’ve tested it on known CZ and sapphire and it hasn’t given a positive result, but you must make sure you are only touching the stone.

As long as you follow the instructions it works! Was able to confirm with this tester that I had a diamond.Only complaint was product description wasn’t clear that it didn’t come with a 9v battery like some other diamond testers do. Was able to dig one out of an old detector so I didn’t have to buy one.

I was impressed by the way it looks however I test real diamond as well as metal nickels dimes, it all showed real diamond..

i have had five diferent kind of diamond testers ALL of them work great if you use them correctly there not hard to use but people dont read how to use them its not" rocket surgery"

I didn't receive anything that told me specifically how to use this, however it wasn't too difficult tune it in and then test it on a diamond you'll get the hang of it.