Here's why:
* Reshiram isn't found in a Light Stone. Reshiram is a Legendary Pokémon and is found in the Victory Road area of the game.
* Light Stones aren't used to revive Pokémon. Light Stones are used to evolve certain Pokémon, like Eevee into Sylveon.
To encounter and capture Reshiram in Pokémon Black and White, you need to:
1. Complete the main story. You need to become the Champion of Unova by defeating the Elite Four and the Champion.
2. Go to Victory Road. Once you've become Champion, you can access Victory Road again.
3. Travel to the top of Victory Road. Reshiram will be waiting for you in the final area of Victory Road.
4. Prepare for battle. Reshiram is a very powerful Pokémon, so be sure to bring your best team.
Once you've defeated Reshiram, you can catch it and add it to your team.