Hello! That's a fantastic question, as 1921 was a very important year for United States silver dollars. The value of your coin really depends on which of the two different "Liberty" silver dollars minted that year you have: the Morgan Dollar or the Peace Dollar.
The 1921 Morgan Silver Dollar is by far the more common of the two. Over 86 million of these were produced across the Philadelphia, Denver (D), and San Francisco (S) mints. Because they are so common, a 1921 Morgan in average circulated condition is generally valued in the range of $25 to $40, which is close to its actual silver melt value. If the coin is in pristine, uncirculated condition, its value can climb higher, potentially up to several hundred dollars for top-grade examples.
On the other hand, the 1921 Peace Silver Dollar is a much rarer and more valuable coin. This was the very first year the Peace Dollar was produced, and it was struck in "high relief," giving the design a distinct, deep look that was changed in later years. This makes it a key-date coin for collectors. A 1921 Peace Dollar, even in a lower, circulated grade, is typically worth at least $100. For coins in better condition, the value rises sharply, easily reaching several hundred to even thousands of dollars for uncirculated specimens.
To figure out which one you have, you can look at the portrait of Lady Liberty. The Morgan Dollar has a classic-style profile, while the Peace Dollar features a more modern-looking profile with a radiate crown. The eagles on the reverse are also quite different. For an exact value, getting the coin professionally graded is always the best course of action.
