The Eugenie Blue Diamond among other diamonds in the Smithsonian's collection. The round yellow diamond in the back weighs about 12 carats. The Shepard Diamond is the large yellow cushion shaped stone, weighing 18.30 carats. The round brilliant white diamond is the Pearson Diamond, weighing 16.72 carats. The pink pear shape weighs 2.86 carats, and the two uncut green diamonds weigh 2.05 and 0.97 carats. The round yellow diamond weighs about 12 carats.