Where's the File for the Special Folder Icons?

Pretty sure my failure to find an answer to this via Google is my inability to find a good way to phrase my question! XD You know how in the Home Folder the "Documents", "Pictures", etc folders have special icons? When I move one of them out of the Home folder and put it back, the icon reverts to the default folder icon. I remember a few years ago I found a file that had a list of addresses to the folders in question, but I can't remember where it is!