antique 1800s, four 4 side spike rifle or musket socket bayonet, Civil War vintage

Antique 19th century rifle or musket socket bayonet. This bayonet measures 23" long overall and about 20" long on the blade. The blade is fluted on four sides. The socket for the rifle barrel measures about 3/4" in diameter. It is rusty. We don't know much about this bayonet, but were told that it is probably from around the Civil War.