1964 Nickel No Mint Mark

Only the 1942 through the 1945 nickels with the large mint marks above the Monticello have any silver content. They are 35% silver but have a reduced amount of copper and contain no nickel. Both of these metals were needed for military use.

Nickels minted in 1942 were struck in the normal 75% copper, 25% nickel alloy as well as the 56% Copper, 35% silver and 9% Manganese alloy, but they can be differentiated by the use of the large P and D mint mark on the silver alloy issues.

The nickel returned to the original copper/nickel alloy in 1946 and returned to the smaller mint marks as well.

with the above...
The only pure silver coins are the silver bullion coins minted recently. Many of our silver coins are called coin silver, or 90% silver, 10% copper. The nickel you posted is your typical looking 1964, some just tone differently than others giving it that silver look but not silver. Of course, 1964 is the last year for 90% silver for only the dimes, quarters, and halfs.

the war time nickels minted all have a huge mint mark about the dome, and they are only 40% silver.

Actually, "why do you think this is silver?" is a legitimate question to help give you the correct answer to your question, and I would have asked the same if I got to it first. If you think it may have been struck on the wrong planchet, the answer would be to ask you what the weight was. If you just mistakenly felt all 1964 nickels were silver, then the answer would be what was presented here. The more information you give, the easier it is to give you the help you are asking for.

@Vanillacake and @ Icutier:

The question WHY (do you think? or do you state this...?) are legitim questions to ask in order to give the right answer. Suppositions circulate in thousands, but are just supposition and nothing real could bring those been true.
Here in fact every day all we can learn something, but no one will be teaching someone. This Hobby is a self teaching from different opinions and answers.

To this coin: The Nickel after years of circulation will have a silver color due to the oxide deposit at the surface. The 1964 wrong planchet must be excluded because never happened in normal Mint production for that year. The history of the 1964 Mint production of the coins exclude this hypothesis.