The Hope Diamond is a 45.52 carat fancy dark grayish-blue diamond currently in the possession of the Smithsonian Institution in Washington, DC. In its current state, the Hope Diamond has been cut into a round brilliant shape with additional facets along the pavilion, or base of the stone, to bring out the rich color and sparkle of the diamond. It is set into a white diamond necklace which includes 61 other diamonds, and is among the most famous diamonds in the world, thanks to its unusual history and color. The distinct blue color of the Hope Diamond is believed to be caused by boron impurities in the stone, which has been categorized as VS1, meaning that the diamond is faintly clouded when examined under a microscope.
The history of the Hope Diamond starts in the 1600s, when the stone was purchased in India by a French merchant, Jean Baptiste Tavernier. At the time, the stone was roughly diamond shaped, was 112 2/16 carats, and was probably found in the Kollur Mine in Goldonda, India. Tavernier described the diamond as a brilliant violet, and sold it along with many other diamonds to Louis XIV in 1668. In 1673, Sieur Pitau cut the stone down to 67 carats, and it came to be called the "Blue Diamond of the Crown" or simply the "French Blue." It remained part of the royal estate, and in 1749 was reset for Louis XV. In 1792, the diamond was stolen, along with many other court jewels, during the French Revolution, and it vanished underground for twenty years.
The next record of the Hope Diamond occurs in 1812, when a large blue diamond emerged in England, and several jewelers suspected that it was the famous French Blue. The diamond changed hands several times before appearing again in the personal catalog of Henry Philip Hope, the Hope Diamond's namesake. No indication about the origin of the stone was made, and it changed hands, sometimes acrimoniously, several times before being sold to Cartier, in Paris.
In 1910, Cartier showed the Hope Diamond to a wealthy young client, Evalyn Walsh McLean, who initially did not like the diamond because of its setting. Cartier reset it into a headpiece, which was later turned into the necklace currently on display in the Smithsonian. The Hope Diamond became intimately associated with Walsh, who wore it frequently, along with a large collection of other precious stones, until her death in 1947. Her diamond collection was purchased in 1949 by Harry Winston, who put the Hope Diamond on display for 10 years before donating it to the Smithsonian, where it remains today.
The Hope Diamond has several interesting properties which were revealed under closer examination after the stone was acquired. The stone actually has a reddish cast under certain light, although this color is not visible to the naked eye. It is possible that when Tavernier first purchased it, the violet color was more apparent, and subsequent cutting and recutting of the stone changed the nature of the stone's color. The stone also exhibits delayed florescence. Like other diamonds, it will glow dully under ultraviolet light. When the light is removed, however, the Hope Diamond flashes a deep red color before fading. It is also believed to be cursed, due to its complex and sometimes notorious history.