It is grey metal so Im not sure if all the bluing is gone or if it is an old nickel process. Only a couple tiny specks of rust so Im going to guess nickel. There is some crud/corrosion in the barrel and it looks pitted but I have not cleaned it, just put some oil on it. It might polish up nice as the rifling looks ok.
IT is the break top where the barrel swings up to take the cylinder out. Not sure of the caliber as it is not marked anywhere on the gun. Dark wood grips in good shape. No safety. Im thinking it was made in the 1800's some time based on the dates stamped on the barrel rib.