--- title: "diamond tester — Niche Verdict: Skip it (51/100) | Amazon United States - Flapen" canonical_url: "https://flapen.com/amazon/research/us/arts-crafts-sewing/diamond-tester" last_updated: "2026-07-10T02:37:46.588Z" locale: en meta: description: "a concentrated shelf (top 5 take 90% of clicks) — diamond tester doesn't clear our bar today." "og:description": "a concentrated shelf (top 5 take 90% of clicks) — diamond tester doesn't clear our bar today." "og:title": "diamond tester — Niche Verdict: Skip it (51/100) | Amazon United States - Flapen" --- Back to Flapen home # **diamond tester** **Skip it****51/100 ** a concentrated shelf (top 5 take 90% of clicks) — diamond tester doesn't clear our bar today. **Market/yr** **$2.7M** **Growth (1y)** **+169.6%** **Products** **9** **Brands** **9** was 7 a year ago **Sellers** **12** **Price range** **$9.15–$239.57** **Returns** **5.9%** **Rating** **4.0★** **Skip it** Scored 51/100 across market size, growth, competition, quality gap, and returns. Market sizeGrowthCompetitionQuality gapReturns Market size **53** ×0.30 Growth **73** ×0.30 Competition **0** ×0.20 Quality gap **82** ×0.10 Returns **51** ×0.10 ## **Demand** Weekly Amazon search volume, last 104 weeks — +169.6% year over year. 31K15KHoliday '24Holiday '25Spike '26Jul '24Nov '24Mar '25Jun '25Oct '25Feb '26 ## **Seasonality** Monthly demand index across the year — 1.00 is average. JFMAMJJASOND No pronounced peak months · busiest ÷ quietest = 1.4× ## **Competition** - HMKIS44% - Siziviki18% - Hqdz15% - Valkynos10% - Marvelity3% - Hqdz-td3% - Other (3 brands)7% The top 5 products capture 90% of clicks — a locked-up shelf that new listings rarely crack. 9 brands and 12 sellers compete here. **Brands** **9 **▲rising was 7 a year ago **Sellers** **12** **Top 5 brand share** **90%** #ProductBrandPriceRatingReviewsClick shareTrend 1 ![HMKIS Diamond Tester Pen Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier Diamond Selector for Novice and Expert (Non-Rechargeable)](https://m.media-amazon.com/images/I/41YOr1285DL.jpg) [**HMKIS Diamond Tester Pen Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier Diamond Selector for Novice and Expert (Non-Rechargeable)**](https://www.amazon.com/dp/B08MTG5NHJ) HMKIS$16.984.1★8,31344%▼falling 2 ![Diamond Tester Professional Jewelers Gemstone Detector High Accuracy Diamond Checker Pen Professional for Jewelers Gem Tester (Jewelry-Only Detection)](https://m.media-amazon.com/images/I/41Z3o3G6kQL.jpg) [**Diamond Tester Professional Jewelers Gemstone Detector High Accuracy Diamond Checker Pen Professional for Jewelers Gem Tester (Jewelry-Only Detection)**](https://www.amazon.com/dp/B0B5DHYMWX) Siziviki$10.954.1★94818%▲rising 3 ![Diamond Tester High Accuracy Jewelry Diamond Tester Professional Diamond Tester Pen Jeweler Tool for Novice and Expert - Diamond Selector II 9V Battery Included(Black Diamond Testers)](https://m.media-amazon.com/images/I/51zV2YIJ0QL.jpg) [**Diamond Tester High Accuracy Jewelry Diamond Tester Professional Diamond Tester Pen Jeweler Tool for Novice and Expert - Diamond Selector II 9V Battery Included(Black Diamond Testers)**](https://www.amazon.com/dp/B06Y2MT175) Hqdz$15.274.1★7,51615%▼falling 4 ![Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Portable Gem Checker for Novice & Experts Battery Included](https://m.media-amazon.com/images/I/41AgO8KzPjL.jpg) [**Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Portable Gem Checker for Novice & Experts Battery Included**](https://www.amazon.com/dp/B0F9PM2YGV) Valkynos$33.414.3★19810%▲rising 5 ![Diamond Tester Pen High Accuracy Jewelry Tester Battery Included Gemstone-Only Detection - No Metal/Gold Testing for Novice and Expert Gemologists](https://m.media-amazon.com/images/I/41Yx5utCLRL.jpg) [**Diamond Tester Pen High Accuracy Jewelry Tester Battery Included Gemstone-Only Detection - No Metal/Gold Testing for Novice and Expert Gemologists**](https://www.amazon.com/dp/B0G6BPDHCZ) Marvelity$9.153.1★313%▲rising 6 ![Diamond Tester High Accuracy Diamond Tester Pen Environmental Protection 9V Battery Professional Diamond Selector for Jeweler Novice and Expert Thermal Conductivity Meter (Diamond Tester)](https://m.media-amazon.com/images/I/41u52kcj3AL.jpg) [**Diamond Tester High Accuracy Diamond Tester Pen Environmental Protection 9V Battery Professional Diamond Selector for Jeweler Novice and Expert Thermal Conductivity Meter (Diamond Tester)**](https://www.amazon.com/dp/B0DTS53RMS) Hqdz-td$15.634.3★1073%▼falling 7 ![Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE](https://m.media-amazon.com/images/I/51pTzeoh0rL.jpg) [**Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE**](https://www.amazon.com/dp/B0BY3N4KBD) GTE$38.174.3★7043%—flat 8 ![High Accuracy Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Diamond Tester Professional Jewelers Gemstone Detector (Diamond Tester Pen)](https://m.media-amazon.com/images/I/41t3a3NOLJL.jpg) [**High Accuracy Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Diamond Tester Professional Jewelers Gemstone Detector (Diamond Tester Pen)**](https://www.amazon.com/dp/B0GQHMR4Q9) UVER$38.044.3★202%▲rising 9 ![GemOro UltraTester 3+ Diamond Tester | Test Diamond Moissanite White Sapphire Gemstone | Precision Tool with Expert Professional Reading & Accuracy](https://m.media-amazon.com/images/I/31uCmWa0J1L.jpg) [**GemOro UltraTester 3+ Diamond Tester | Test Diamond Moissanite White Sapphire Gemstone | Precision Tool with Expert Professional Reading & Accuracy**](https://www.amazon.com/dp/B00QUGGK3Y) GemOro$239.573.8★2092%▲rising ## **Product shelf** All 9 tracked products in this niche. Top sellersNewestTrending [![HMKIS Diamond Tester Pen Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier Diamond Selector for Novice and Expert (Non-Rechargeable)](https://m.media-amazon.com/images/I/41YOr1285DL.jpg)**HMKIS Diamond Tester Pen Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier Diamond Selector for Novice and Expert (Non-Rechargeable)** HMKIS**$16.98**4.1★8,313 reviews](https://www.amazon.com/dp/B08MTG5NHJ) [![Diamond Tester Professional Jewelers Gemstone Detector High Accuracy Diamond Checker Pen Professional for Jewelers Gem Tester (Jewelry-Only Detection)](https://m.media-amazon.com/images/I/41Z3o3G6kQL.jpg)**Diamond Tester Professional Jewelers Gemstone Detector High Accuracy Diamond Checker Pen Professional for Jewelers Gem Tester (Jewelry-Only Detection)** Siziviki**$10.95**4.1★948 reviews](https://www.amazon.com/dp/B0B5DHYMWX) [![Diamond Tester High Accuracy Jewelry Diamond Tester Professional Diamond Tester Pen Jeweler Tool for Novice and Expert - Diamond Selector II 9V Battery Included(Black Diamond Testers)](https://m.media-amazon.com/images/I/51zV2YIJ0QL.jpg)**Diamond Tester High Accuracy Jewelry Diamond Tester Professional Diamond Tester Pen Jeweler Tool for Novice and Expert - Diamond Selector II 9V Battery Included(Black Diamond Testers)** Hqdz**$15.27**4.1★7,516 reviews](https://www.amazon.com/dp/B06Y2MT175) [![Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Portable Gem Checker for Novice & Experts Battery Included](https://m.media-amazon.com/images/I/41AgO8KzPjL.jpg)**Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Portable Gem Checker for Novice & Experts Battery Included** Valkynos**$33.41**4.3★198 reviews](https://www.amazon.com/dp/B0F9PM2YGV) [![Diamond Tester Pen High Accuracy Jewelry Tester Battery Included Gemstone-Only Detection - No Metal/Gold Testing for Novice and Expert Gemologists](https://m.media-amazon.com/images/I/41Yx5utCLRL.jpg)**Diamond Tester Pen High Accuracy Jewelry Tester Battery Included Gemstone-Only Detection - No Metal/Gold Testing for Novice and Expert Gemologists** Marvelity**$9.15**3.1★31 reviews](https://www.amazon.com/dp/B0G6BPDHCZ) [![Diamond Tester High Accuracy Diamond Tester Pen Environmental Protection 9V Battery Professional Diamond Selector for Jeweler Novice and Expert Thermal Conductivity Meter (Diamond Tester)](https://m.media-amazon.com/images/I/41u52kcj3AL.jpg)**Diamond Tester High Accuracy Diamond Tester Pen Environmental Protection 9V Battery Professional Diamond Selector for Jeweler Novice and Expert Thermal Conductivity Meter (Diamond Tester)** Hqdz-td**$15.63**4.3★107 reviews](https://www.amazon.com/dp/B0DTS53RMS) [![Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE](https://m.media-amazon.com/images/I/51pTzeoh0rL.jpg)**Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE** GTE**$38.17**4.3★704 reviews](https://www.amazon.com/dp/B0BY3N4KBD) [![High Accuracy Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Diamond Tester Professional Jewelers Gemstone Detector (Diamond Tester Pen)](https://m.media-amazon.com/images/I/41t3a3NOLJL.jpg)**High Accuracy Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor Fast 0.5s Detection Diamond Tester Professional Jewelers Gemstone Detector (Diamond Tester Pen)** UVER**$38.04**4.3★20 reviews](https://www.amazon.com/dp/B0GQHMR4Q9) ## **Reviews** What buyers praise and complain about, mined from review topics. ### **What buyers love ** **Ease Of Use**24% *“straightforward it is”* **Value For Money**14% *“Good value for the money”* **Quality-Overall**14% *“A great quality tool that is very reasonably priced”* **Advertised Vs Actual Product**11% *“it works as advertised”* **Efficiency**9% *“It works ok”* **Instructions/User Manual/Troubleshooting**4% *“The included instructions were helpful”* **Weight Light**3% *“The pen is lightweight”* **Measurement/Reading Accuracy**2% *“It does give accurate reading”* **Durability**2% *“Its made very durable”* **Functionality-Overall**1% *“efficient in meeting my needs”* ### **What buyers complain about ** **Functionality-Overall**22% *“stopped working”* **Quality-Overall**20% *“Low quality product”* **Durability**7% *“Doesn't last”* **Measurement/Reading Accuracy**6% *“Unreliable results and questionable accuracy”* **Instructions/User Manual/Troubleshooting**6% *“terribly written directions”* **Value For Money**4% *“CRAPPY I SHOULD HAVE KNOWN BY THE PRICE”* **Battery Life**3% *“The non-rechargeable battery dies quickly”* **Ease Of Use**3% *“is not convenient to use”* **Strength**3% *“The detection probe is fragile and loose, slow response and hard to operate stably for long time use”* **Advertised Vs Actual Product**3% *“False reading on moissanite”* #### **Top return reasons**- Functionality-Overall47% - Advertised Vs Actual Product8% - Defective Material/Parts7% - Measurement/Reading Accuracy7% - Value For Money5% - Instructions/User Manual/Troubleshooting4% - Quality-Overall4% - Certifications3% - Charging3% - Ease Of Use2%