This enchantment will give a purple glow to the weapon.
The enchantment has 6ppm (procs per minute), and normally does 30 Shadow damage that can be resisted (partially or wholly), and even amplified (some reports have said they received up to 92 health on some mobs in Blackwing lair]. Damage inflicted is converted into healing. Rogues with Quick Recovery will not receive a healing bonus with this proc. However, the healing bonus is not reduced when the receiver is under the effect of a Mortal Strike.