There are many ways platinum jewelry is marked. Jewelry artisans mark platinum for the same reasons they mark gold. They want their clients to know the value and purity of the metal they use.
Platinum is also measured in troy ounces, which means it has 31.1 grams per ounce. Platinum can use the same karat designations as gold, with 24 karat being pure. Having said that, platinum is rarely marked with the K mark. It is generally done in percentages. Marks include “Platinum”, “Pt”, “10% Irid. Plat”
Gold is often mixed with copper, zinc, nickel, or silver to make the lower karat weights. Platinum is usually mixed with Iridium or Rhodium or other metals in the Platinum family. The percentage of platinum in a ring is almost always 90% or higher.
Some rings with diamond settings will be marked 14k or 18k and then say ”Plat”. These rings are not platinum. They are gold and used platinum on the head of the ring.
We hope this helps you. Old Pueblo Coin are gold, platinum and silver buyers in Tucson, Az. We are happy to pass along years of knowledge so that you are better informed on the ins and outs of gold, platinum and silver buying. Check back again soon!