The Antique pin does not have a mark but was tested with platinum acid and a " kee" tester to be solid platinum. It weighs 1.9 grams and is 3/4" in diameter. The pin is round and holds 16 natural pearls that range from 1.8 to 2 mm in size. It also has 4 rose cut natural diamonds and 8 square lab created blue sapphires which can be typical for this time period. This piece is in nice condition.