Projectiles pierce another target on minions

I wanted to get a nice amulet for myself, and was thinking of getting a new one with
+1 to skeletons and a projectiles pierce another target.
The thing is, Im a skeleton mage summoner build and wanted to know if the 'Projectiles pierce another target' applies to them as well, or is it better to get some other prefix(maybe + to mana)?

none of your modifiers affect minions unless specifically stated otherwise