What is the value of a 1921 silver dollar?

It is hard to say, because two different types of silver dollars were issued in 1921 with very different values. This was the last year for Morgan dollars and the first year for Peace dollars. The simplest way to tell the two apart is on the reverse of a Peace dollar the eagle is standing on a rock with its wings folded, the Morgan has the wings spread out.

1921 Morgan dollars regardless of mint-marks are the most common date of all Morgans. A circulated coin has a retail value of $32.00-$40.00. Morgan dollars were issued from 1878 to 1904 and again in 1921, the obverse (front) of the coin has a portrait of Miss Liberty with the motto E PLURIBUS UNUM above her head, on the reverse the eagle has its wings spread out. The Peace dollar was also issued in 1921 to 1928 and 1934 & 1935 the obverse of this coin has the Word LIBERTY above Miss Liberty's head and on the reverse the eagles wings are folded and it's standing on a rock with the Word PEACE on it.

The values between the two are very different.

MORGAN: $23.00-$26.00 in circulated condition.

PEACE: $80.00-$185.00 in circulated condition.

See the related links for more information. An uncirculated 1921 silver dollar is worth about $32 to $35 and up. A coin of that denomination in good condition is worth about $26 to $27. The silver value is about $21 as of July of 2014.