It means you have a proof dime that was struck at the San Francisco Mint.
If the coin isn't in its original protective packaging, someone broke up the set and spent the coins. Unfortunately when a proof coin is taken out of its package and exposed to other coins its value drops to only that of a normal circulated coin.
On the reverse of the coin under the wreath. It's a S or O mint mark, but without a mint mark it was struck in Philadelphia.
If it has one, it is on the reverse under the wreath and can only be an "S"
From 1946 to 1964, the mint mark position was at the bottom left of the torch on the back of the coin. No mint mark = Phila. S = San Francisco D = Denver
The mint mark position on all "Mercury" dimes is next to the E in ONE on the back. No mint mark = Philadelphia S = San Francisco D = Denver
It can only be an O or S and is on the reverse of the coin.
A 1970 Uncirculated Mint set would not have a dime with a "S" mintmark, only a Proof set will have a dime with a "S" mintmark for that year, so no your mint set is not rare.
As of 12/2008, Numismedia quotes the fair market value (FMV) at $1310.00
On the reverse of the coin under the wreath. It's a S or O mint mark, but without a mint mark it was struck in Philadelphia.
The missing mintmark 1968-S dime is only found as a PROOF coin in the 1968 proof sets. If you think you have one of these coins that has been removed from a proof set, it would have to be authenticated by a major grading service.
No mint mark - $2 to $4 depending on wear "S" mint mark - $2 to $15
If it has one, it is on the reverse under the wreath and can only be an "S"
The mint mark position on all "Mercury" dimes is next to the E in ONE on the back. No mint mark = Philadelphia S = San Francisco D = Denver
From 1946 to 1964, the mint mark position was at the bottom left of the torch on the back of the coin. No mint mark = Phila. S = San Francisco D = Denver
$1.75 with no mint mark, uncirculated $35 D mint mark, $2.50, uncirculated $90 with S mint mark, $1.75, uncirculated $40
It can only be an O or S and is on the reverse of the coin.
The mint mark position on all Mercury dimes is to the right of the E in the word ONE on the reverse of the coin. No mint mark = Philadelphia D = Denver S = San Francisco
The mint mark position on all Mercury dimes is to the right of the E in the word ONE on the reverse of the coin. No mint mark = Philadelphia D = Denver S = San Francisco