Minelab PRO-ALLOY Gold Purity Tester

$ 375.00

The PRO-ALLOY Gold Purity Tester is here. The PRO-ALLOY Gold Tester is the perfect addition to every detectorist’s toolkit, giving the ability to test the gold karat rating of gold rings and jewelry without the need for messy chemicals or causing damage to that potentially valuable find.


  • Instant gold karat reading
  • Fast and accurate
  • Non-destructive
  • Protective case included
  • Batteries included (1xAA)

What's included:

  • PRO‑ALLOY meter
  • Test probe set
  • 1 x AA battery
  • Protective meter cover
  • Soft carry case
  • Multi-language instructions

PRO-ALLOY is now available for order in the USA.

So now that you’ve found your fortune detecting – how much is it worth?

That’s the potential dilemma facing every successful detectorist – you may know a friendly reputable jeweller who pays ‘top dollar’ for your treasure finds, or do you take your chances at the nearest unknown pawn shop?

While golden treasure may be instantly recognisable as soon as you uncover it, the gold karat purity rating could be anything from 9K to 24K and that dirty silver ring could even be platinum in disguise!

With the PRO‑ALLOY gold tester there’s no messing around with dangerous acids or having to scrape away a portion of your find and potentially damage its intrinsic value. Just place your item on the test plate, touch it with the attached probe, and determine its gold purity from the easy-to-read scale.
PRO‑ALLOY is battery powered, so you can use it at home or take it detecting and cash in your finds on the way home!


Gold Karat Ratings

Jewelry will often carry a hallmark or stamp to denote what it is made of and it's purity. Jewelry is sometimes stamped incorrectly, so be ahead of the game and double check your finds before you sell them!

24K 999 99.99%
23K 959 95.80%
22K 916 91.60%
21K 875 87.50%
18K 750 75.00%
14K 585 58.50%
9K 375 37.50%

Karat Hallmark Purity (Fineness)
The graph shows some common gold karats, their hallmark and corresponding gold purity (fineness).

Some jewelry is constructed from different alloys, and this might not be visually obvious. E.g, the claws holding a gemstone might be 9K gold while the band is 18K. PRO‑ALLOY can test the different parts of a single item to help identify their karat rating


Colored Gold Alloys

18 karat gold is not always the same color. Below are elements that are commonly used in gold alloys, and color types to look out for.*

Gold, normally yellow, can be alloyed with additional elements to alter its color. If you've found something that looks fake, it pays to check it anyway as it could contain gold.

Replacement PRO-ALLOY cables (Part No. 3011-0310) and a Protective Meter Cover (Part No. 3011-0311) are available for individual sale.

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