Everybodies heard about the infamous diamond called the Koh I Noor that was seized by the East India Company in 1849. I've been reading a book about the Maharaja of the Punjab Duleep Singh and this particular diamond....it is a fascinating read indeed and explains how it got into the hands of the Royals; such a pity! A stunning diamond nevertheless!
Queen Mary's Crown made by Garrard & Co, used to contain the Koh-i-Noor diamond as well as the Cullinan III and the Cullinan IV. However, in 1914 these diamonds were replaced by crystal models. It contains approximately 2,200 diamonds and was specially constructed so that the arches could be removed, as seen here.