The U.S. does not have a "M" mintmark. Look at the coin again and post new question.
Assuming it's circulated and has no mintmark, retail value is $16.00-$21.00
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).
If it has a mintmark it's on the reverse just above the letters DO in DOLLAR.
The 1921 Morgan regardless of mintmark is the most common of all Morgan dollars. An circulated coin is $37.00-$44.00
1921 is the highest mintage most common of all Morgan dollars, circulated coins are valued at $16.00-$19.00 Value can be higher if it has a mintmark, up to $22.00For the series of Morgan dollars 1921 is the highest mintage year. Assuming the coin is circulated and depending on grade and mintmark, retail values are $16.00-$25.00
Assuming it's circulated and has no mintmark, retail value is $16.00-$21.00
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).
For the series of Morgan dollars 1921 is the highest mintage year. Assuming the coin is circulated and depending on grade and mintmark, retail values are $16.00-$25.00
The coin is called a MORGAN dollar and 1921 is the most common of all of them, assuming it's circulated and regardless of mintmark it has a value of $16.00 to $26.00
If it has a mintmark it's on the reverse just above the letters DO in DOLLAR.
The 1921 Morgan regardless of mintmark is the most common of all Morgan dollars. An circulated coin is $37.00-$44.00
The mintmark if it has one is in the same place on all Morgan silver dollars, it's on the reverse just above the letters DO in dollar. If it does not have a mintmark it was coined in Philadelphia no Morgan dollar has a "P" mintmark. The only mintmarks used on Morgans are O, S, CC and a D was used in 1921 only.
1921 is the highest mintage most common of all Morgan dollars, circulated coins are valued at $16.00-$19.00 Value can be higher if it has a mintmark, up to $22.00For the series of Morgan dollars 1921 is the highest mintage year. Assuming the coin is circulated and depending on grade and mintmark, retail values are $16.00-$25.00
For the series of Morgan dollars 1921 is the highest mintage year. Assuming the coin is circulated and depending on grade and mintmark, retail values are $16.00-$25.00
1921 is the only year Morgan dollars were struck at the Denver Mint. No other dates could have a "D" mintmark. All 1921-D Morgan's have a tiny or "micro" mintmark.
A average Mint State 1921 Morgan is $30.00-$40.00
For the series of Morgan dollars, 1921 is the highest mintage, most common year. Assuming the coin is circulated and depending on grade and mintmark, retail values are $31.00-$38.00 A typical Mint State (MS-60 to MS-63) coin is $40.00 to $50.00 depending on mintmark.