What can and cannot critically strike?

[Supe]

What can and can't critical is something that is confusing me. As far as I can tell, there is three different types of critical strikes: weapon, mind, and spell. And it appears that damage causing abilities that do not fall into these three categories do not critically strike.

Please correct me if I'm wrong, but these are the things I have found that do not crit:
Shattering Shout (still testing, but I haven't hit a critical yet)
Runes
Wands (I don't understand the mechanics behind these things at all. Do they scale with a stat? I could never get a Shadowstrike critical with a Wand)
Damage over Time abilities that do not specify they can crit

I'm sure there are others, but these are the ones I have encountered so far. I was hoping Shattering Shout could critical strike, but I am beginning to have my doubts (I don't even know what critical stat it would use).

[HousePet]

Can confirm that shattering shout cannot crit.
Most runes cannot crit.
Wands do not crit.
Damage over time abilities can crit (but usually don't), and they will only do so once, when they are being applied.
Runes are actually spells, and any generalisation about what can and can't crit will be just an approximation.
I don't think there are any specific rules.

[Supe]

Crap. I was really hoping Shattering Shout could. Well, gimmick build hopes aside, can you specify which runes you have found to crit? My only experience has been with Acid Wave and never getting a critical strike from it (from Stealth w/ Shadowstrike--so I don't know if that changes anything)

[HousePet]

Rune of the Rift is the only Rune that can crit.