Experience Watchmaking & Jewelry Repair

Gold isn’t the only metal you might find yourself in a position to buy. You may find yourself confronted with people wanting to sell platinum. Use this guide to learn the ins and outs of testing platinum. When you are testing for platinum, you will approach the process in much the same way you would with testing gold: you’ll use the testing stone again and use acid to determine the metal content of the piece you are testing.


Tools Needed:

Step 1

One thing to pay attention to and be aware of before testing for platinum is that iron and steel items will pass the streak test for platinum so before attempting a streak test, you should always start by testing any suspected platinum with a powerful magnet.

If the metal is attracted (strongly) to the magnet, it can be one indicator – but Cobalt is sometimes present in 950 platinum so its not a defining test.


Step 2

Once you have ruled out steel and iron, take the item and scratch it along the surface of the stone like you would with any piece of gold. Make sure that you have a thick and visible deposit line that you can test accurately and is about 1 inch long.


Step 3

Apply a drop of your platinum testing acid across the streak on your testing stone.

Note:If you will not be testing platinum often, you can use 22 karat gold acid to test for platinum. However, if you plan to be testing platinum with any sort of regularity, you will want to invest in a platinum testing acid.




Step 4

Identify the reaction. If the metal you are testing is platinum, the streak should keep its bright white coloring for over a minute of exposure to the testing acid.

Be aware that other than iron and steel, there are plenty of other white non-magnetic metals that will give false platinum reading like chromium cobalt, dental materials, some class rings and some metals frequently used in stainless flatware. Always try to verify your results in more than one way whenever possible.


We can also suggests heating the platinum red hot with a butane torch, when cooled the Platinum will remain the same color as when you started since it does NOT oxidize giving further proof.


  • Richman

    Hi. My wife’s £15,000 platinum engagement ring is magnetic and a neodymium magnet will pick it up easily. This is due to it being alloyed with 5% cobalt, the other 95% is fine platinum.

    Your comment ‘If the metal is attracted to the magnet, you are not dealing with platinum’ isn’t really correct in all cases. Platinum is difficult to identify, and wasn’t even hallmarked or assayed in the UK until 1975, so all suspect platinum jewelry should go the full range of tests before dismissing