The coat of arms is unmistakably that of Peru, however, being a 20 centavo piece with the word "Oro" (gold) below is odd. I would like to check my reference books but I'm away from my home right now. Definately an odd cool piece.
It was to raise funds to build monuments around Peru for this guy - I want to share this webpage with you https://es.wikipedia.org/wiki/Miguel_Grau_Seminario *oops sorry it's in Spanish English - https://en.wikipedia.org/wiki/Miguel_Grau_Seminario