It seems like you might be mixing up some information. Here's why:
* Surf is a move: The move you're likely thinking of is "Surf", which allows Pokemon to traverse water.
* Crystals are items: While there are various crystals in the Pokemon games, they're usually items that enhance Pokemon or are used for evolution. They are not moves.
If you can provide more context about where you encountered this information, I might be able to help you figure out what you are looking for.