Logan Sapphire
The Logan Sapphire is a sapphire from Sri Lanka. The mixed cushion-cut stone was owned by Sir Victor Sassoon and then purchased by M. Robert Guggenheim as a gift for his wife, Rebecca Pollard Guggenheim. She later gifted the sapphire to the Smithsonian Institution in 1960; its name is derived from her new surname after remarrying to John A. Logan. As of 2022, the Logan Sapphire is on display in the National Gem Collection of the National Museum of Natural History in Washington, D.C. Description. The Logan Sapphire weighs and is approximately the size of a large  chicken egg, measuring . It is a mixed cushion-cut sapphire (having a rounded rectangular shape) and is blue with slight shades of violet. The cut is designed to highlight its color rather than its brilliance. In June 1997, the Gemological Institute of America determined that the Logan Sapphire had not previously undergone heat treatment (a technique that is sometimes used to enhance the color or mechanical properties of gemstones) and that its color was natural. It fluoresces reddish-orange when exposed to ultraviolet radiation. This phenomemon, as well as the slight violet tones, indicates trace amounts of chromium in the  sapphire's structure. The Logan Sapphire is one of the largest faceted blue sapphires in the world. It is set in a silver and gold brooch and surrounded by 20 round brilliant cut diamonds weighing, in total, approximately . The diamonds were likely taken from an antique bracelet or necklace. A 1958 article in "Ladies' Home Journal" by Rebecca Pollard Guggenheim, its owner at the time, suggests that it was set in the brooch sometime after she acquired it several years earlier. History. The sapphire was mined from Sri Lanka. It likely originates from Ratnapura, the "City of Gems". One of  its early owners was Sir Victor Sassoon, 3rd Baronet of Bombay, a member of the wealthy Sassoon family. According to the Smithsonian Institution, the Sassoons may have acquired the sapphire from an Indian maharaja. Sassoon planned to auction the sapphire in 1941 to raise money for the British war effort during World War II, but the auction did not take place. In the early 1950s, the American diplomat M. Robert Guggenheim purchased the sapphire from Sassoon as a Christmas and anniversary present for his wife, Rebecca Pollard Guggenheim. In "Ladies' Home Journal", she recalled her reaction upon seeing it: "I  was simply overcome. [...] It's simply not a stone you could wear casually. All I could think was, I'll never be able to wear it. And of course, I loved it." She deeded half of it to the Smithsonian Institution in December 1960, a year after Robert's death, and the remaining half the following year. The transaction was only in deed; the sapphire was not physically divided. She wanted it to be reserved to be worn only by the First Lady of the United States, though it has never been used for this purpose. Rebecca Guggenheim changed her  surname to Logan in 1962 after remarrying to John A. Logan, a management consultant, and the sapphire became known as the "Logan Sapphire". It was one of several gifts from wealthy donors that came after the Smithsonian's acquisition of the Hope Diamond in 1958; another was the Napoleon Diamond Necklace. The Logan Sapphire was finally physically transferred to the Smithsonian in April 1971. As of 2022, the Logan Sapphire is on display in the National Gem Collection of the National Museum of Natural History in Washington, D.C. (catalog number NMNH G3703-00). It is the largest and heaviest mounted  gem in the collection.