23mm, Post Civil War reproduction of a Confederate Navy Button. These buttons are shown in Albert's as unauthenticated.   They were certainly made after the Civil War and first appeared during the Centennial of the American Civil War with letters of authenticity from England.   They look old and have been confused for authentic Confederate Naval buttons for decades.  I suggest buying one as a reference and develop a working memory of it (handle and memorize it)... this will save you real money, later!  These have honest age (being 60 or so years old) and make a fine "place filler" in a collection for a Confederate naval branch of service button, too.