Ah, the 1921 silver dollar, a coin with a bit of an identity crisis! It's a fantastic question because 1921 was a unique year where the U.S. Mint produced two different silver dollar designs: the classic Morgan Dollar and the brand-new Peace Dollar. The location of the mint mark depends entirely on which one you're holding.
While the provided search results were a bit tight-lipped on the exact location, I can spill the numismatic beans for you.
First, check which dollar you have. If it's a Morgan Dollar, the one with Lady Liberty in profile and a thinner eagle holding arrows, flip it over to the reverse side. The mint mark is a tiny letter located just below the tail feathers of the eagle, nestled above the letters "D" and "O" in the word "DOLLAR".
If your coin is a Peace Dollar, featuring a more modern, tiara-wearing Liberty and a majestic eagle at rest, the mint mark is also on the reverse. You'll find it on the lower left, just below the word "ONE" and to the left of the eagle's tail feathers.
Now for the twist. If you've scoured these spots and found absolutely nothing, don't fret! That just means your coin was minted in Philadelphia. Back then, the Philly mint was too cool to use a mint mark, so a blank space is its own special indicator. Your coin will have either a 'D' for Denver, an 'S' for San Francisco, or the proud emptiness of a Philadelphia original.
