When testing for Platinum (PT), a simple test you can do is the heat test utilizing your jeweler’s torch or portable butane torch. All the tools used in this test can be found in your simple testing tool kit outlined in our August 13th blog. The first step in verifying if a piece is Platinum is to look for the stamp. Most Platinum will be stamped with PT, PLAT, PT900 or PT950. The most common percentage is 90% Platinum with a 10% platinum family alloy like Iridium or Ruthenium. The 95% Platinum mix usually has cobalt as the 5% alloy. In the case that your customer wants the precious metal piece back or you want to resell the item, be sure to either take out or protect any stones you may have that could be damaged by the heat. The purpose of the heat test is to see if the piece will remain blackened or discolored (oxidized) after heat is applied and the item has cooled off. Platinum will not oxidize at any temperature; it will simply return to its original look and state. If you are able to, file into the piece in question to get through any Rhodium plating that may be present (See Fig 1).