They are simply small letters placed somewhere on the coin. They are used to identify what mint they came from.
The "D" & "S" mintmarks are the only mintmarks used for the coins in 1975 & 1976
Those are the mintmarks where the coins were made. D= Denver. P= Philadelphia.
U.S. coins have mintmarks. P= Philadelphia, D= Denver.
Coins have mintmarks not codes. Mintmarks on Buffalo nickels are on the reverse under FIVE CENTS and can only be a D or S.
The U.S. does not have any "F" mintmarks. Only P-D-S & W for any coins.
For 1939 all US coins still have the mintmarks on the reverse.
Look at the mintmark again. The Carson-City Mint struck it's last coins in 1893. The only mintmarks this coin can have are a D or S.
Coins with filled mintmarks are very common. It's only face value.
By looking at the coin. Modern coins made for circulation have the mintmarks on the front. P= Philadelphia. D=Denver.
Of all the Morgan dollars, the 1921 coins are the highest mintage most common. Regardless of mintmarks, values for circulated coins are $31.00-$40.00.
The mintmarks are placed on different places on different denominations of coins minted prior to 1968. In order to know where to look you need to know which coin you have and where the mintmark is located on that particular coin. Since 1968 the mintmarks "D" and "S" have been on the obverse [heads] side of the coin near the date. Since 1980 the Philadelphia mint has also placed their mark, a "P", on all the coins minted there with the exception of the Lincoln Cent which bears no mintmark for Philadelphia.
No, only a "D" Mintmark will be on a 1922 Lincoln cent. The Denver Mint was the only Mint to strike Lincoln cents in 1922. Some of the coins were struck with very worn dies that caused the Mintmarks to be weak or completely missing. The coins with missing Mintmarks can be very valuable.