Yet another metal detecting mystery,Welcome to the hobby!!! If one of 3 pieces ring up as silver,Id have them tested because it could be part of something containing silver plate that was in a fire or melted down eons ago,the one ringing up as sliver may have more silver content then base metal compared to the other two,I could be talking out my azz right here and im sure someone else will say they know what you have but if i were you,id have at least one of the three tested.Just my two cents....
HH John