The large Art Deco brooch has been tested with nitric acid and a "kee" tester to be solid platinum. It weighs 17.6 grams and measures 2 5/8" x 1 1/2". There are 3 round European cut natural diamonds across the center with an approx total weight of .73 cts. The piece also holds over 100 rose cut natural diamonds. This pin / brooch is in very nice condition.