"Breakfast at
Tiffany's" didn't hurt the name, but there is no character named
Tiffany in that work. The now-forgotten Broadway play "
Mary,
Mary", which had a character named
Tiffany who was the beautiful young romantic rival to the character
Mary (and was made into a 1963 film itself) probably had as much to do with the idea that
Tiffany could be an appropriate name for a girl.