I think that Numismatic is more used to the study of currency (coins or paper money), and not so much to say "coin collection". But if there is only one word to talk about coin collection, Numismatic should be the one.

There are two types of 1921 silver dollar coins. One is the Morgan Silver Dollar and the other is the Peace Silver Dollar. Check both faces of the coin and that will help you to identify what coin you have. But instead of trying to sell those coins, why don't you start your own collection? … Read more

You need to collect more information about your coin, to say that it is a 1921 silver dollar, is not enough. You need to check the layout on both sides of the coin and also the mint mark. With that information you will be able to find the value easier and accuratly.