For coins dated 1906 to the present, it means the coin was made at the Denver Mint. A "D" mint mark on an old (1838-1861) gold coin means it was made at the long-closed gold coin mint at Dahlonega, GA.
The D mint mark on any coin minted since 1906 indicates it was made at the Denver Mint.
Look at the coin again. The first coin struck at the Denver Mint was in 1906 What you have is a Mint medallion that was included in coin sets for many years. They were struck on cent blanks. The date is the year that the Treasury Department was established.
Mintmarks identify which mint the coin was made at.
38,612,000 Liberty Head nickels were made in 1906. All were struck at the Philadelphia Mint.
On a US coin, D is the mint mark for Denver, CO (1906 and later) or Dahlonega, GA (1838-1861)
The letter is known as the mint-mark and tells where the coin was made. A coin having a P mint-mark (or no mint-mark on some coins) was made in Philadelphia, a coin having an S Mint-mark was minted in San Fransisco, a coin with a D mint-mark was minted in Denver.
On a US coin, D is the mint mark for Denver, CO (1906 and later) or Dahlonega, GA (1838-1861)
The Dahlonega mint closed in 1861 and the Denver mint opened in 1906 so you could not have a 1904 coin with a D mint mark. Please check again, if the letter is an O it indicates your coin was made in New Orleans. If so, as of 07/2008 it's worth $16 to $20 depending on how worn it is.
Yes - U.S. dimes, quarters, and half dollars all had similar designs in 1906 The "lady" you refer to is Miss Liberty!! To determine what your coin(s) value is, please post a new question, one for each coin, with its denomination. Also look on the back to see if there is a small letter D, O, or S - that's the mint mark and tells where the coin was struck. In some cases the mint mark can have a big effect on a coin's value.
That's not a D mint mark, because the Denver mint didn't begin production until 1906.
Coins made at the Philadelphia mint did not have mint marks until the 1980s. Your coin was made at the Philadelphia mint.