+ Critical Rate on potential weapons

That's pretty cool. If you have +critical chance on two different equips, is it chance +(X1+X2)% for +100% damage? Meaning, does +50% damage come from both crit sources and stack with itself? Would it all stack with stun mastery and SE?

Edit: Upon further inspection, weapons are apparently the only thing to give +crit rate/damage anyway. Aside from gloves giving miniSE that is.