Technically the coins are supposed to be called Liberty dimes and the winged Liberty cap worn by Miss Liberty is supposed to symbolize freedom. But the design looks so much like the winged helmet worn by the Roman god Mercury that people nicknamed the coin a "Mercury" dime almost as soon as it was released, and the name has stuck for almost a century.
Mercury's surface looks similar to the moon's surface, with craters, plains, and mountains. Both Mercury and the Moon lack an atmosphere, leading to similar erosion and impact patterns on their surfaces.
It Looks Like Our Moon Just 40% Bigger
It shows a female portrait, facing left, which is meant to represent Liberty, wearing a liberty cap with small wings. The wings give Miss Liberty a similar appearance to the Greek god Mercury, hence the coin's nickname. See the below site for a photo:
Need the date, condition and variety to give a meaningful estimate. Draped Bust dimes (1796-1807), Capped Bust Dimes (1809-1837), and Seated Liberty dimes (1838-1860) were all minted with 13 stars on the obverse. Prices in these series range from $16 for a common date SL that is worn but recognizable to $70,000 for a scarce 1822 CB in perfect condition.
A mercury dime has a face of a personification of liberty on it with a winged helmet. They are called mercury dimes because it looks like Mercury from mythology.
See this page: http://cointrackers.com/coins/148/1945-mercury-dime/ for what the 1945 "mercury" or "winged liberty" dime looks like.
The woman on the Mercury Dime is Lady Liberty with a winged headdress called a Liberty Cap. The wings signify freedom. The image looks very much like a picture of the Greek god Mercury who used his winged helmet to fly through the heavens. Because of that the coin was mistakenly called a "Mercury" dime almost from its first day in circulation, and the name has stuck for nearly a century.
Your dime is normally called a Barber dime after its designer. All Barber dimes from 1892 to 1916 used the same design. There's an excellent picture at the link below
The letter W is the initial for Adolph Weinman, who designed the coin.
The overstamp looks like there is a 1 in front of the 2 in "1942" and is quite noticeable.However, there is a variety of the 1942-D Mercury dime that is a 2 over 1 also which is less noticeable, for this the best indicator is to look at the "4" it will have what looks like a second tail under it and the "2" will look to have dot right under the far left base.
Chances are, if it is the same size or looks like a dime, it may be counterfeit.
The letter W stands for Weinman. Adolph Weinman designed the coin.
The date looks almost like "19412", with the 1 and 2 squashed together. Check the image at the Related Link. The overdate is fairly clear but it may help to use the zoom tool on your browser to expand the picture a bit.
In the search box on your browser type in "Mercury Dime" click images an then search. It will show you many pictures of Mercury dimes.
Mercury dimes were minted from 1916 to 1945. Your coin, like all US dimes minted since 1946, carries a picture of Franklin D. Roosevelt so it's called a Roosevelt dime. Please see the Related Question for more.
Mercury dimes were minted from 1916 to 1945. Your coin, like all US dimes minted since 1946, carries a picture of Franklin D. Roosevelt so it's called a Roosevelt dime. Please see the Related Question for more.