A coin with an S mintmark means is was made at the San Fracisco Mint.
A "clear" S mintmark is one where the "S" is very distinguishable. The "filled" S mintmark is one where the "S" is more blob like (it looks more like an 8 than an S)
Look on the back below the DO in DOLLAR. It could be black or there could be a small O, S, or CC mintmark. Value as of June 2012: No mintmark:$52 "O" mintmark:$156 "S" mintmark:$52 "CC" mintmark:$540
While 1910 is not a rare date for Barber dimes, it is silver, so at a minimum it has a current silver value of about a dollar. You also need to check the back, near the bottom, for a mintmark. There may be a "D" or an "S" there. With full rims on both sides, and an "S" mintmark, it's worth about $3.00 If all the letters of LIBERTY on the headband are readable, then with no mintmark it's worth $2, with a "D" mintmark it's worth $6, or with an "S" mintmark it's worth $35 If all the details are strong, with only a slight amount of visible wear, then with no mintmark it's worth $15, with a "D" mintmark it's worth $35, or with an "S" mintmark it's worth $80 If your coin is a nice uncirculated example, then with no mintmark it's worth $75, with a "D" mintmark it's worth $150, or with an "S" mintmark it's worth $300
The mintmark will be on the reverse of the coin under the wreath. The mintmark will either be a D or S or may have no mintmark, in the case of a coin with no mintmark it was minted in Philadelphia.
For a Lincoln cent, any mintmark is under the date on the obverse. Indian Head cents have the mintmark on the reverse under the wreath and can only be an "S" mintmark, on just on the 1908 & 1909 issues.
If it is a "s" quarter it will always have the S mintmark. You can find this mintmark usually on the back of the coin. The exact location will depend on the type of quarter.
It's simple. A 1922 S silver dollar will have a S mintmark while a 1922 D silver ill have a D mintmark. The mintmark is located on the reserve below the word "ONE".
It will have a S mintmark.
If it is a proof then it will have the mintmark "S". If your coin doesn't have the mintmark "S" then it is just a normal coin.
In general no. Prior to 1980 only the D&S mintmark's were used. Coins struck at the Philadelphia Mint did not use a mintmark. From 1980 to date the Mint added a "P" mintmark. But some Proof sets have Dimes that lack a S mintmark, they do have much higher values.
Because the "S" mintmark means the coin was minted in San Fransisco. Because the coins minted in San Fransisco in 1976 were not intended for circulation, they are more desirable to collectors. Some of the "S" mintmark coins are 40% silver and that boosts their value. If the coin has no mintmark, or any other mintmark other than "S" it has no value beyond face value.
If it has the D mintmark it means it was made at the Denver mint. If it has the S mintmark it means it was made at the San Francisco mint.