The Hope Diamond is one of the world's most famous gems - renowned for its nearly flawless clarity, rare deep blue color, and eventful history. It was formed more than a billion years ago at a depth of about 150 km. The diamond was brought to the earth's surface by a volcanic eruption. The rare blue color of the jewel is attributed to light interaction with an impurity in the diamond's internal atomic structure. As the diamond grew, a few atoms of boron entered the crystal structure. In 1668, Jean-Baptiste Tavernier, a French gem merchant, sold the diamond to King Louis XIV of France. During the French Revolution it was stolen, and did not reappear until 1812 in London. Evidence suggests that King George IV of England purchased the recut diamond in 1820. Sometime after George IV's death in 1830, the diamond was purchased by Henry Philip Hope, whose name it bears today. After Hope's death in 1839, the diamond was left to his family. In 1901, after undergoing many more ownership changes, the diamond was sold to a series of merchants, including Pierre Cartier, who designed the current setting. In 1912, Cartier sold the Hope Diamond to Evalyn Walsh McLean, a Washington, D.C. socialite. Finally, in 1949 Harry Winston purchased the diamond, including it in his Court of Jewels collection, which toured the world for charity. In 1958, Harry Winston donated the Hope Diamond to the Smithsonian Institution, where it remains today. The Hope Diamond is currently in a platinum setting, surrounded by sixteen white pear-shaped and cushion-cut diamonds, suspended from a chain containing forty-five diamonds - the original design by Pierre Cartier around 1910. The Gemological Institute of America (GIA) graded the Hope as a natural fancy deep grayish blue diamond with a clarity grade of VS-1. For more information please see "The Hope Diamond" under the "Gems and Minerals" section of the Dynamic Earth.