
it is a mint error. It is caused by die attrition. The dies are gradually altered by repeated contact with planchets. The dies transfer design elements to each other right through the coins they strike. It is also referred to as Ghosting, or Internal Metal Displacement Phenomenon - depending on which expert you talk to. It's a good example of Lincoln's outline on the reverse. The price is a rip though, the dies were commonly over-used in the 40's and 50's making Ghosting errors plentiful.