A large 45.52 carat, fancy deep grayish-blue diamond, housed in Smithsonian Natural History Museum in Washington D.C. the ?Hope Diamond? is legendary for the curse it puts on whomever possesses it. The diamond appears blue to the naked eye due to the presence of small traces of boron within it. It exhibits a red phosphorescence under ultraviolet light. When exposed to ultraviolet light the diamond glows a mysterious red.

The phosphorescence of the diamond comes from boron present in the stone, an element that makes it appear blue in normal light and red when exposed to ultraviolet light indicating a different mix of nitrogen with boron. Historians believe that the diamond was cut from a larger gem that was first found in India. The diamond is thought as an historic gem and is considered as a rare scientific specimen that has an ability to provide vital insights into our knowledge of diamonds and their formation.

The deep blue diamond is the centerpiece of gem collection at the Natural Museum of Natural History. The hope diamond is the most powerful jewel on display. It is described as fancy dark grayish-blue. The stone exhibits an unusually intense and strongly-coloured type of luminescence; after exposure to long-wave ultraviolet light, the diamond produces a brilliant red phosphorescence that persists for some time after the light source has been switched off. The diamond is believed to be a part of the stolen French Blue crown jewel. The diamond is believed to be cursed. The diamond was stolen from a Hindu statue. It was believed to be one of the two eyes of the idol, and when the diamond was found missing a curse was placed on whoever owned the diamond. The legend claimed that Tavernier had died of the fever soon after he owned the diamond. The diamond was also blamed for the fall from the king's favor of madame, the beheadings of Louis XVI, mutilation and beheading of the Princesse de Lamballe.

Some may consider these characters as fictitious, but the history still remains unverified. A diamond cutter Wilhelm Fals was killed after his son Hendrik had stolen the diamond. There are many such instances which prove that the owner of the diamond had met their misfortune either by death or being broken financially. Even with its curse the stone came to be known as blue diamond of the crown or the French blue. The diamond was set in the gold and suspended on a neck ribbon for the King to wear on special ceremonial occasions. The diamond was claimed to be owned by many. Finally it was donated to Smithsonian by jeweler Harry Winston, the now 45.52 carat gem stone is the world's largest blue diamond.