"The Hope Diamond"

Arguably the most famous Diamond in the world. It is an Antique Cushion Cut, weighs 45 carats and is Blue in colour! 
One of the major reasons it is famous is due to a reputed curse, that people who wear or own it have bad luck or tragedy befall their lives. A look at the facts does not bear out that the diamond is indeed cursed!
Named thus as it was once owned by Henry Phillip Hope.
Today it calls home the Smithsonian Natural History Museum in Washington D.C., where anybody can view it, having been donated by Harry Winston in 1958.
Studies on the geometry of the diamond has revealed it as originating with a 115-carat stone found in India in 1668. That stone was sold to King Louis XIV of France who had it cut into the 69-carat French Blue. The French Blue was stolen during the French Revolution.
Just over 20 years later, after the statute of limitations expired, a large blue diamond was quietly put up for sale in London, and eventually Henry Philip Hope purchased it.
Value today $200 million+ USD.