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💎 Test like a pro, inspect like a boss — never miss a real diamond again!
The HMKIS Diamond Tester Pen combines advanced thermal conductivity technology with dual power options (Type-C & 9V battery) to deliver fast, precise diamond authenticity testing. Paired with a powerful 60X LED jeweler’s loupe, it offers millennial professionals a sleek, portable solution for confident gem verification and detailed inspection—no specialized training required. Adjustable size settings and clear visual/audio feedback ensure reliable results across micro to large diamonds, making it an essential tool for jewelry managers, collectors, and enthusiasts aiming to stay ahead in the luxury market.









| Asin | B08MTG5NHJ |
| Best Sellers Rank | #5,784 in Arts, Crafts & Sewing (See Top 100 in Arts, Crafts & Sewing) #4 in Jewelry Diamond Testers |
| Brand Name | HMKIS |
| Color | Black |
| Customer Reviews | 4.0 4.0 out of 5 stars (8,519) 4.0 out of 5 stars |
| Global Trade Identification Number | 09070190994879 |
| Included Components | 60X Microscope |
| Item Dimensions | 10.16 x 2.17 x 1.38 inches |
| Item Highlight | Based on High Thermal Conductivity of Diamonds. Powered by USB or 9V Battery Diamond Selector for Novice and Expert |
| Item Weight | 120 g |
| Lower Temperature Rating | 5 °C |
| Manufacturer | HMKIS |
| Maximum Operating Voltage | 9 volts |
| Measurement Type | Thermal Conductivity Scale (1-9) |
| Minimum Operating Voltage | 5 volts |
| Model | HXK+FDJ |
| Number Of Items | 5 |
| Number Of Packs | 1 |
| Part Number | HMKIS |
| Power Source | Battery Powered |
| Specification Met | CE, RoHS |
| Style Name | Appraising jewelry, gemstones, unique rocks, calligraphy, paintings, antiques, and other collectibles, as well as offering expert evaluations for gems, fine jewelry, diamonds, coins, stamps, and watches. |
| Unit Count | 1 Count |
| Upper Temperature Rating | 30 °C |
User
Amazing product
This is an absolute gem of a find. Works very well and includes everything necessary for it's use. The microscope includes a UV light where you can check fluoresce and has good magnification for smaller stones. The tester itself can be powered by a battery or USB-C cable, which is more accurate and convenient. The tester can differentiate between glass and high hardness stones like Corundum, but struggles if you are testing similar hardness stones like corundum and moissanite. Overall would recommend a lot.
User
A great instrument
It works very well. Quality made. Price is rt. A great help for my business.
User
Meh
Came to write a review right from the order page, but it's a different combo of products from what I ordered, so bear with me here. Odd.I read all directions both online and that came with tester. I watched all the videos. What I missed until I came back to the product page is that the tip DOES NOT depress, so don't try to press too hard! Another thing was that the scale light will traverse green, yellow, red and back until it is warmed up (see video). And lastly, the tester remains on whether you turn it off or not for as long as it is plugged into the USB. It did NOT come with a 9V battery as described in the product description, so I can't say if it does that with a battery in it.It worked as described, though inconsistently. I figured out that the copper tester tip had a burr on it that wasn't allowing it to make complete flat contact. I used one of my jeweler's files to very gently take that burr off and it works well now. Won't give me a RI number as I had hoped, but it does test diamonds.The little dish they give to hold stones while you test them is about useless...the stones slide around as you try to test - I suggest investing in a good pair of locking tweezers. I'm digging the 60x lighted loupe, though it's kind of silly for gemstones because you need light to pass through the stones, not onto the stone, to see flaws and inclusions, but the UV appears to be 365 which is great as long as it's not reflecting back into your eyes. Im going to figure out a way to mount the loupe over a light. 60x shows much more than my 10x.Carry cases are cheap but functional. I didn't try the USB C cord because I keep one plugged in at my desk already.Final word: It works, but I will be investing in the fancy Presidium.UPDATE: After testing several known diamonds over the course of several days, this unit quit working (no, it didn't get too cold, no breeze, I allowed it to reheat after each stone, I followed the directions). I didn't pay much, so it's not worth the hassle of trying to return it. Besides, I do still like the lighted loupe! ;)
User
Recommend
Fun gadget
User
Garbage that doesn't work
Garbage that doesn't work. When I put it up against a diamond that I know for a fact is real. It says it's real and beep at me. When I put it up against a random piece of metal, it says it's real and beeps at me. When I put it up against a garbage blue looking gem that I'm pretty sure is plastic, it says it's real and beeps at me. No matter what I touch this thing against, it tells me it's a real diamond and beeps at me. Yes, I read the instructions. Yes, I watched videos on how to calibrate it. This thing does not work at all.
User
Broken after 4 months
Broken after 4 months. When powered on, Keeps beeping. Does not stop. So sad. Was great when working.
User
Well worth it!
I’ve been purchasing jewelry from overseas and use this to verify
User
A sparkling companion for gem enthusiasts. Seeing is believing with the Magnifier. WORKS!
I recently got my hands on this diamond tester pen, and I couldn't be more happy with it. As someone who loves jewelry, this tool has made identifying genuine diamonds, moissanite and CZ a breeze. It truly does differentiate CZ from Moissanite and Moissanite from Diamonds! It offers precise readings that help me differentiate between real diamonds and imitations effortlessly. The pen is incredibly easy to use, providing quick and accurate readings that give me confidence in my purchases. It fits comfortably in my hand, and the sleek design makes it a joy to use. I also appreciate how portable it is; I can take it anywhere and test stones on the go to show friends. Just a single use could save you from fraudulent stones claiming to be one thing and then are something else. Everyone should have this tester at home. I cannot say enough good about this item. This little gadget has truly elevated my jewelry-buying experience so I never get taken. You gotta get one. Highly, highly recommended. : )
User
Die Lupe funktioniert nicht
Als wir das Gerät ausprobiert haben, mussten wir leider feststellen, dass die Lupe ihren Zweck nicht erfüllt. Der Gerät selbst ist in Ordnung. Wir wollten diesen Produkt zurück geben, nun leider wurde uns gesagt, dass wir den Rückversand erstmal selber übernehmen müssen. Die Sendung kam aus USA und den Rückversand hätte uns noch 50€ gekostet, von daher haben wir diesen Artikel behalten. Ich wollte den Verkäufer gerne kontaktieren, aber dies ist auch nicht möglich.....
User
مجموعة قيمة
Very nice, good material
User
Super
Super article, fonctionne super bien. Je recommande.
User
Don’t buy
Don’t buy
User
Slowest start up time.
Very slow to start.Takes ages to get ready for testing.Unbelievably slow.
Trustpilot
2 weeks ago
3 weeks ago