The Cullinan II Diamond. Note the two tiny platinum loops on the edges.  This is so the stone can be worn as a brooch, alone or with the Cullinan I   attached. However, it usually resides in the front of the Imperial State Crown. Bijoux, Diamond Mines, Diamond Cuts, Gem Diamonds, Cullinan Diamond, Royal Jewels, Crown Jewels, Gems And Minerals, Fine Jewelry