File:Standard 75x75 collect rob hopediamond 01.gif The Hope Diamond is a large, 45.52 carats (9.10 g), deep-blue diamond, housed in the Smithsonian Natural History Museum in Washington, D.C. The Hope Diamond is blue to the naked eye because of trace amounts of boron within its crystal structure, but it exhibits red phosphorescence under ultraviolet light. It is classified as a Type IIb diamond, and is famous for supposedly being cursed. It is currently unset for the first time since it has been on display.