I know this is ridiculous BUT is there such thing as a 1966 Silver Roosevelt Dime i have a collection of silver coins and im pretty sure its made of silver Does anyone know a way to test it?

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.