This lapel pin is made from Gutta Percha, a form of rubber. It is ¾ 0f an inch across and cone shaped. The back as a small brass piece used to fit in a buttonhole. Attached is an old tag that reads "made by a soldier at Fort Warren 1865".

Fort Warren is located in Boston Harbor and was built from 1833-1861. It was completed shortly after the beginning of the American Civil War. During the war, the island fort served as a prisoner-of-war camp for captured Confederate army and navy personnel, elected civil officials from the state of Maryland, as well as Northern political prisoners.