Question about what's considered a spell or skill?

while working on a bow build I ran into a question for myself:

Should I grab +%Spell damage for Explosive Arrow or Poison arrow or even Lightning arrow?

Then I realized: as far as I know there's no way to tell what constitutes as a spell or a skill. Some directly work as physical (i.e. Dual Strike) so you know they're not spells, but in the case of say Lightning Arrow, you shoot out an arrow (physical) that deals lightning damage (spell????)

I'd like to know how you can tell what gems the (+%Spell Damage) effect and which arrow skills are upgraded by these nodes =)

Yeah, they really need to add clarity to this one.

A spell can be cast without a weapon equipped. An attack (even a gem one) requires a weapon (other than Elemental Hit) and calculates its damage and attack speed from that weapon as well as any relevant attack speed bonuses.

If you hit 'c' and click on the skill icon, it'll say 'casting speed' or 'attack speed'. I believe this information is also displayed in the mouse-over for the skills at the bottom right, but might be wrong there.

Basically, a spell has cast time, an attack skill has attack speed.

You can't rely on any other factor to figure it out -- not colour of gem, not the damage type inflicted, not the range. There are too many anomalies there, after all. Ethereal Knives is a GREEN gem that deals PHYSICAL damage at just over MELEE range. And it's a spell.

Conversely, Lightning Strike is a RED gem that deals LIGHTNING damage at very LONG range. And it's an attack.

...For your arrows, you want ranged damage nodes, fire and elemental damage nodes and buffs for your explosive arrows (I THINK -- definitely for burning arrow, at least).

In short, spell damage will not affect your magical arrows.

Thank you for the help with this. I'm looking to make an explosive arrow build thats a bit tanky (seems like it should work quite nicely) and I needed to know what nodes to pick up. Thanks again for the help ^^

Look at the skill description (in your skill bar in the lower right) and check if it sais:
- cast speed (than it is a spell)
- attack speed

:)