Do you have to use a type of stone evolve Eevee umbreon?

You don't need a stone to evolve Eevee into Umbreon. You need to level up Eevee at night with high friendship.

Here's how:

1. Ensure Eevee's friendship is high. You can increase friendship by feeding it berries, battling with it, and walking with it.

2. Level up Eevee at night. The exact time of day varies depending on the game, but it's generally considered nighttime when the sun has set.

Once these conditions are met, Eevee will evolve into Umbreon.