23mm, Post Civil War reproduction of Confederate Navy Button, restruck by Courtney & Tennent, Charelston, South Carolina. These buttons shown in Albert's as unauthenticated.   They were certainly made after the Civil War.   They look old and have been confused for authentic Confederate Naval buttons for decades.  I advise buying one as a reference and develope a tactile memory for it... this will save you a thousand dollars or more later!  They also 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..