Rare Antique Platinum Ring With TanzanitesAntique ring likely from the 1930s was originally set with diamonds as tanzanite was not discovered at that time. We bought the mounting and updated it with very high quality tanzanites weighing 1. 50 carats total weight. This is a rare ring which has maintained it high quality because platinum wears so well and will last many more generations. The ring is set with . 25 carats of diamonds.