No, what you are seeing is not the mintmark, but the designer's initials (the "W" mintmark would not be used until the 1980s) the mintmark (if any) would be found on the back of the coin after the "E" in "ONE"
They don't exist, the first Roosevelt dime was 1946. With a date of 1940 the dime is a MERCURY dime and is common with average values of $1.00-$3.00 depending on condition.
The "W" you see is not a mintmark. It' the monogram of the designer A. A. Weinman. The mintmarks are on the reverse of the coins. 1940 is a common date, most are only valued for the silver, about $1.50.
Dancing on a Dime - 1940 was released on: USA: 1 November 1940
Such a coin does not exist. A "dime" is the slang term for a US 10 cent coin.The Royal Mint has never produced "dimes" or 10 cent coins.
If you have a 1940 Roosevelt dime it is fake. The Roosevelt dime was not produced by the US Mint until 1946.
All Mercury Head dimes have the "W" it's the designers initial, Adolph A. Weinman he also designed the Liberty Walking Half dollar.
Ten cents was the value of the dime in 1940.
1940 dime were only made from 90% silver. See the related question below for more information.
If it is a circulated dime, then it is worth about $1.00, mostly depending on the value of silver
A 1940 Mercury dime (not Liberty) is very common. If it shows any wear, the value is just for the silver, about $1.90.
Priceless. No barber dimes were minted anywhere near 1940.
90% silver, 10% copper.