If you are not sure it is actually silver, drop it on a hard surface like tile or kitchen marble counter. A dull ring is silver and a resounding clank is not. It will also have a smell. Thats how I determine if something is stirling at yard sales and so.
Well it is silver as it is an issue of 1958, Canada didn't stop using silver until after we did, if memory serves me rightly I think in 68 or 69, either way this falls well before that so it is 80% silver!~ Thanks for listing!