Tiffany Blue is the slang name for the medium-light robin blue associated with Tiffany & Co., the New York-based jewelry company founded in 1837 by Charles Tiffany and John Young. The color was used on the cover of The Blue Book of Tiffany, first published in 1845. Since then, Tiffany & Co. has used the color extensively on promotional materials such as boxes and bags. The color Tiffany Blue has been a registered color trademark of Tiffany & Co. since 1998. It is produced as a private spot color by Pantone, with the number PMS 1837, the number derived from the year Tiffany was founded.