Crystal Spear of Hegaroth

Using the crystals you have gathered form a perfectly smooth crystal spear in your hand. It is 20 ft long and weighs nothing to you. For others it weighs 2000 pounds. Think of the target you wish the spear to find, which can be a place person or object. The spear will find it's target. The spear reaches it's target if it's on the same plane of exstience in 10 minutes. 

The spear crashes into the ground next to the target, or if in a specified place lands in the center of that place, and makes a giant 300ft crater that's 50ft deep. Everything in that area takes 80 points of bludgeoning damage in a giant explosion. Creatures in that area must succeed on a Dexterity saving throw against your spell DC taking half damage on a succses.