Does increased spell damage work on all spells?

Hello this is probably a noob question but I couldn't figure this out on my own.

So, if I have a wand that has a % increased spell damage does that increase only the damage of spells socketed into the wand or does it increase the damage of all my spells including the ones that are inserted into other items (gloves, helmets, shield etc)?

I also have the same question for gloves or anything else that increases spell damage.

It's a global modifier on gear, meaning it's on ALL spells. Obvious exception is linked gems with Q, as some of those add LOCAL % Spell Damage, which only works on linked spells. Q on Heralds adds Global % Fire/Cold/Lightning Damage, however.