Diablo 1 HD Hellfire Mod | Awake

Was looking at this Infernal Torch.

I play a rogue so I don't need. But I am curious what is spell power.

How does it work?

If sorceror has +100% spell power does it equal to 2x damage?

It's similar to % enhanced damage for physical attacks. Not sure if it's applied last in the formula when calculating spell dmg (as in +100% = 2x dmg), but anyway it's good to have.