I added a photo with the weight. I am not sure if it’s silver or nickel. As I said in pervious comments I just find this in pocket change. But I checked and the year 1964 is silver year sorry I do not know how to help more.
Could have been made as a dime holder filler coin by a dime collector that couldnt find the particular dime for the slot so made like a pewter replica? Not sure.