The "S" mint mark is used by the San Francisco Mint.
Today San Francisco makes proof coins sold to collectors, but for many years they produced coins for general circulation as well. All denominations were made until 1954, dimes and cents were made in 1955, cents and nickels were made from 1968 to 1974, and dollars were made in 1979 and 1980.
Yes they are, all "S" Mint 1971 & 1972 Eisenhower dollars are 40% silver, but ONLY for those two years. In 1973 the Mint added copper-nickel clad "S" Mint coins along with the 40% "S" Mint silver coins
The mint mark "S" on US coins means the coin was minted in San Francisco, California. For more information concerning mint marks visit the site at the related link, below. Coins produced at the Denver mint have a "D" and those at the Philadelphia mint have either no mint mark (for pennies and coins before 1980) or a "P" for all other denominations. Coins produced at the mint at West Point, NY (largely bullion coins, although some 1996 dimes were produced there) have a "W" mint mark.
Philadelphia, coins made before 1980 with no mint mark were struck at that Mint
Please check your coin again and post a new, separate question. The San Francisco Mint was inactive from 1956 to 1964 inclusive, so there are no 1961-S coins of any denomination. The SF Mint was reactivated to strike Special Mint Sets and some circulating coins beginning with the 1965 dates, but these coins didn't carry mint marks. The S mint mark was resumed on proof coins beginning in 1968. In addition, SF minted some cents and nickels for circulation from 1968 to 1974; all of these also have an S mint mark.
Current retail values are $15.00-$24.00 for circulated coins. Mint state coins start at $28.00
San Fransisco
No the San Francisco mint struck no coins in 1963.
The U.S. uses mnemonic mint marks so San Francisco coins carry an S mint mark.
In the grade of MS-60, the P & D mint coins are $1.27 the S mint are $1.38
The S above the date is the mint mark for the San Francisco mint and identifies it as a proof coin for the Eisenhower seires of dollar coins.
S and P aren't grades, they're mint marks indicating where a coin was struck. There are many other possible mint marks for U.S. coins as well, depending on their denomination and date.
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