The original weight at minting was 26.73 grams. Of course a circulated coin will weigh slightly less.
Check the weight. A genuine U.S. Peace silver dollar should weigh 26.73 grams. If it's a replica, the weight will be off.
The nominal weight of all Peace dollars is 26.73 grams.
The standard weight of all Morgan and Peace dollars is 26.73 gm.
large silver coin 38.1mm liberty head in God we trust 1929, reverse: 'United States of America' eagle 'one dollar ' PEACE
The is no 1921S Peace dollar; Peace dollars were not produced in San Francisco ("S" mintmark) in 1921. If your 1921 dollar coin is a Peace dollar, it was produced in Philadelphia and has no mintmark; if it has an "S" mintmark, it is a Morgan dollar produced in San Francisco).
They stopped making the Peace dollar in 1935.
An unworn Morgan dollar has a nominal weight of 26.7 grams. All Morgan dollars (as well as Peace dollars) were struck in an alloy of 90% silver and 10% copper, so they contain about 24.1 gm of pure silver, or about 0.77 troy ounces.
The image on the 1923 Peace Dollar is that of Lady Liberty.
The 1921 Peace dollar was minted to commemorate the end of World War I.
The last Peace dollar was issued in 1935 so it can't be a 1942 Peace dollar. Look at the coin again and post new question.
On your browser type in " Peace Dollar " and click on images, this is the easy thing to do.
It looks the same as any other Peace dollar.