Crit vs Spell Crit

Does general crit give bonus to spell crit as well? I noticed many builds here for witches go into some of the regular crit passives, like bloodthirst. I wouldn't think that this increases spell crit because there is actually a spell crit specific passive(s), but just wanted to ask.

And if it doesn't affect spell crits... why do witches go for it?

Crit does both.
Crit with spells does just spells.


Why there is no crit with attacks, and why there is a crit with spells only, dunno.

For the purposes of gemmed skills like power siphon, do they use crit from spell crit nodes, or just general crit?

Power siphon is a physical attack, so no spell damage nor spell crit i think

"

Casia wrote:

Crit does both.
Crit with spells does just spells.


Why there is no crit with attacks, and why there is a crit with spells only, dunno.

Are you sure normal critical modifiers, say from passives, affect spell crit?
I thought the only way to increase spell critical chance was to take those passives.

http://en.pathofexilewiki.com/wiki/Critical_Strike_for_Spells

If I can increase spell critical chance with normal critical passive skills, then I would certainly take them.
Otherwise, I would assume they only apply to weapon damage (normal attacks / skill attacks, not spells). This would only work on your wand then, and those don't do any damage to be considered viable, unless you spec for them.

Can someone confirm this for me?

I can confirm it. both kinds of nodes, the ones that say "x to critical strike chance" and the ones that say "x to spell crit" raise the crit level of spells. Did some testing last night.