It means it was minted in San Francisco.
If you want to know the value of a specific coin, please post a new question with its denomination as well as its date an mint mark.
1928-D $3 to $35,000 depending upon the condition of the coin. 1928-S $3 to $85,000 depending upon the condition of the coin.
The Denver mint did not strike any silver dollars in 1928. You may have a 1928-S where the S is indistinct. This coin is worth $20 to $30 depending on condition.
It should be valued at $15 - $30 depending on the condition of the coin.
If you mean a 1928 Peace dollar with No mint mark It's the key date to the series the value in VF-20 is $475.00. I suggest you take it to a coin dealer, because I have seen many 1928 S mint coins with the mint mark removed.
Circulated coins are $25.00-$90.00 Mint State examples are $150.00 or more
If you mean a 1928 Peace dollar with No mint mark It's the key date to the series the value in VF-20 is $475.00. I suggest you take it to a coin dealer, because I have seen many 1928 S mint coins with the mint mark removed.
The mintmark is on the reverse of the coin underneath the "One" in "One Dollar"
If you mean a Peace Dollar dated 1928, it's the key dateof the series. So consult a qualified professional.
If you mean How much is a 1928 Lincoln cent in Mint State condition. Reatil is $10.00
It could mean anything depending on the coin. What country? What year? What denomination? What does the coin appear to be made from?
The only 1928 Peace dollars that are valuable are those made at the Philadelphia mint. These will not have a mintmark. If there is a small S below the word ONE on the back(tails side) of the coin it isn't of the rare variety. if that spot is blank you have a rare coin. You should take it to an expert and have it evaluated.
A semicircle.