Invigorating Earthsiege Diamond

This is mentioned in other comments when you click the item:
50% chance per crit
to heal for 2% of your total life;

*but* from one person's testing it appears to only proc once every 90 seconds - this is now pretty much worthless - you're better off getting the 42 AP+3% crit meta gem, or stam+2% armor meta gem if you're a tank.

A bit more useful for hunters after 4.03 patch.