Crystal Tessellated  Weapon

Weapon (Any Melee Weapon), Rare (Requires Attunement)

You have a +1 bonus to attack and damage rolls made with this magic weapon. When you hit a creature with this weapon, it takes an extra 1d4 force damage.

Crystal Explosion. As an attack action, you can make an attack roll against a target within reach. On a hit, the target takes 5d8 force damage. On a miss, deal 2d8 force damage to all creatures and objects in a 15-foot cone in front of you (which must include the target). You may choose to miss this attack. Once this ability has been used, the weapon's damaging end shatters and reforms at the end of your next turn. This ability can only be used once every 10 minutes.