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Black diamond tester pen with USB power cable and size wheel

HMKIS basic-2025-12 Diamond Tester Jewelry

SKU CH-VM3H-7VWZV MPN basic-2025-12

USB-powered diamond tester with adjustable S and L modes for micro and large gemstones, weighing 0.181 kg

  • Skill levelEasy Use Jewelry Diamond Tester, Diamond Selector for Novice
  • Main colorBlack
  • Product subcategory52151600
  • Size or dimensions#1
  • Product colorBlack
  • Number of items4
  • USB-powered diamond tester for portable gem verification
  • Simple two-minute warm-up lets novices start testing quickly
  • Adjustable S/M/L size selector prevents false readings on different stones
  • Dual-hand metal shielding improves accuracy on mounted jewelry
  • Compact 0.181 kg design fits easily in a jeweller's kit

Diamond tester for novice and expert users

The HMKIS basic-2025-12 diamond tester is a USB-powered device designed to identify diamonds and gemstones. It offers selectable sensitivity modes for small, medium, and large stones. The unit ships in a pack of four and weighs 0.181 kilograms. It is intended for jewellery makers, hobbyists, and professionals needing a portable verification tool.

Check power source and stone size before testing

The tester requires a Type-C USB connection or a 9V power supply for operation; it is non-rechargeable and must remain plugged in during use. Allow two minutes for warm-up until the READY indicator illuminates. You must select the correct size setting — S, M, or L — via the adjustment wheel before testing, as an incorrect setting yields unreliable results. Metal testing requires both hands on the device following the manual instructions.

Thermals noise and power draw in normal use

The device draws power directly from the USB or 9V source with no internal battery to recharge. Continuous testing of small diamonds requires cooling intervals between readings to maintain accuracy. Operation is indicated by LED level meters and an audible tone when the probe contacts a stone. No active cooling fans or moving parts are present, so acoustic output is limited to the alert tone.

How it compares

Measured against everything we stock in Jewelry Making & Bead Kits, at today’s prices. Recalculated every night.

Price $25.99
Pricier than about 88% of the 213 comparable items (median $15.99).

Specifications

Product
Brand nameHMKIS
Product lineDiamond Tester
Model nameBasic-2025-12, Diamond Tester
Product colorBlack
Main colorBlack
Size & build
Size or dimensions#1
Product weight0.181 kg
In the box
Number of items4
More details
Skill levelEasy Use Jewelry Diamond Tester, Diamond Selector for Novice and Expert (Non-Rechargeabe) (Black)

Questions about this item

What comes in the box and does the tester need a separate power source?

The package contains four items including the diamond tester pen, a USB Type-C power cable and a protective cap. The unit is non-rechargeable and must stay connected to a Type-C or 9 V supply while in use.

How do I choose between the S and L size modes on this model?

Turn the adjustment wheel to S for micro-diamonds and tiny gemstones, or to L for stones of one carat and above. If the exact size is unknown, start with the middle M setting.

What does the nine-light level meter with sound indicate during a test?

When the READY light is on and the meter shows all nine lights plus an audible tone, the tester has confirmed the stone as diamond for the selected size mode.

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