A platinum dime would be worth thousands of dollars ... except that there is no such coin. All 1964 dimes were made of 90% silver and 10% copper.
U.S. dimes minted in 1966 contain no silver, and are worth 10 cents.
If it is a US dime, it isn't silver. Silver stopped being used in dimes after 1964, so any dime dated 1965 or later is struck in copper-nickel and are only worth face value.
how much does it cost
The best way to tell would be to weigh it on a sensitive balance. A silver dime would weigh about 2.5 gm while a copper-nickel dime would weigh about 2.27 gm. There have been a few reports of leftover silver planchets being struck accidentally in 1966. More likely, though, your coin has been plated for use in jewelry.
It's a common coin, still in circulation, has no silver and is just face value.
Yes. The 1962 Roosevelt dime is 90% silver.
There is 2.25 grams of silver in a 1960 dime.
There is no silver in a 1990 US dime.
Canadian dimes minted between 1920 and 1966 contain 80% silver and 20% copper.
There are 2.25 grams of silver in a 1935 silver dime. It is made of 90% silver and 10% copper.
Yes - the "Mercury" dime from 1916 to 1945 has 90% silver in it
Please don't assume that every older coin must be made of silver. Canadian 5¢ coins haven't contained any silver since 1921. Since that time they've mostly been made of nickel or plated steel; during WWII they were made of brass.