Where do you find a moon stone in Pokemon black?

You cannot find a Moon Stone in Pokemon Black. Moon Stones are not available in that game.

Here's why:

* Evolution Items: Moon Stones are used to evolve certain Pokemon, like Nidorina to Nidoqueen and Clefairy to Clefable.

* Game-Specific Items: The availability of evolution items varies from game to game. While Moon Stones might be present in other Pokemon games, they are not part of the Pokemon Black and White games.

To evolve your Pokemon in Pokemon Black, you'll need to find different evolution items or utilize other methods like trading or breeding.