The famous Tiffany diamond, flashing yellow beams of light and weighing 128.54 carats, is on loan to the National Museum of Natural History until September.
The jewel, one of the largest fancy yellow diamonds ever discovered, was lent by Tiffany & Co. for a rare trip outside New York.
The diamond, mined in South Africa in 1877, was cut from its original 287.42 carats by famed Tiffany gemologist George Frederick Kunz.
"This is one of the world's great diamonds," said Jeffrey Post, curator of the museum's National Gem Collection. "The color is intense and even in 1878 it made a splash, and Kunz cut it for its brilliance." It has 82 facets instead of the usual 58.
The diamond, which is about an inch wide, will be displayed in its current "Bird on a Rock" setting by Jean Schlumberger -- a brooch with a bird of yellow and white pavé diamonds with a ruby eye perched on top.
Two more images after the jump.