Elemental Blast

 Blast
An elemental weapon has been sheathed in its and deals additional damage on a critical hit and further damage on a Vorpal Strike. Critical hits deal an additional 1d10 damage for a weapon with a x2 critical multiplier, 2d10 for a x3 critical multiplier and 3d10 for a x4 critical multiplier. Additionally, if you roll a 20 while attacking your target and confirm the critical hit (known as a Vorpal Strike from here on), the weapon blasts your target, doing 4d6 more damage.

Found On

 * Most commonly - Tier 3 upgraded Green Steel Weapons
 * Thaarak Wraps (Acid Blast)
 * Elemental Longbow of Earth, L12 and up (Acid Blast)