Papal medal, not a coin. It is in commemoration of Pope Pius IX "on 8 Dec., 1854, in the presence of more than 200 bishops, he proclaimed the Immaculate Conception of the Blessed Virgin as a dogma of the Church." He declared Jesus mother to be The Blessed Virgin Mary and that is the purpose of this medal. No idea of when produced, but I would assume during his life, pre-1878, since it declares him "Pontefice Massimo (Pope)" in "Roma (Rome)". Also, in Italian, not Latin, so specifically for an Italian audience, thus made in Italy most likely. Hope this info, though a little vague, helps.
Hard to be certain from a picture, but the loop appears to be original to the piece, not soldered on later as would occur when converting a coin into a pendant.
