Bests & Worsts Reviews from Amazon

I purchased this item because I had realized I have been burned a few times on buying jewelry that was claimed to be genuine. This item does not only test for diamonds, but you can also gauge the gemstones with this as well. If you know what the hardness of a sapphire or opal is, you can use this to gauge whether or not it's genuine. Ex. The hardness of a diamond is 10. If you know that corundum (ruby/sapphire etc) is a 9 and you test the stone and it ranks up there near a diamond but not quite, then you can assume that the gemstone you're testing is a genuine ruby or sapphire. However, if the "Ruby or sapphire" gemstone ranks very low, you can almost bet that it is maybe a quartz or topaz. Of course, this isn't an exact science with the tester, but it will give you a good idea of if your gemstone is what they are claiming it to be. Hardness scales of random gemstones can be found online everywhere so you can use those for references. The diamond tester, I have found to be rather accurate. You do have to be careful with this item, since if you are trying to test diamond CHIPS or very small diamonds in large settings, and it hits the metal it will go off with a rather loud, continuous beeping noise to say "Error" that it's hitting the metal. Suggestion: Use the tester on a genuine diamond (one you're certain is diamond) so you can get a feel for what it sounds like when it hits the 10 spot on the scale and what sound it makes. Also, try to test it on a metal to also see what it sounds like. Once you know how to read the tester, it'll be very easy to use. Instructions come with it and you can find YouTube videos that will show you how to use this as well. Turn on tester. Set on level surface and wait. 1 red light will come on. Wait for TWO red lights to light up. Once second light is lit up, you are ready to test! Pen for size reference. Comes in a nice case, with velcro closure. Has a pocket on the side to hold your metal diamond/gemstone grounding tool. This is used when a stone is not fixed into a setting. You MUST ground your stone before testing. Comes with a few different size compartments. Overall, great item. I recommend it to anyone that is in the jewelry business, gemstone collecting and even hobbyists buying and selling collections.