Amulet of Equilibrium

This spiraling pendant is made of three magic-sensitive panes of colorful crystal. Each piece of crystal is attuned to a different arcane element. If you cast spells, you can use the amulet as a spellcasting focus while you're attuned to it.

The amulet has 4 charges and regains 2 expended charges daily at dawn. When you deal cold, fire or lightning damage to a single crature while wearing and attuned to the amulet, you can expend any number of its charges to reroll that many of the cold, fire or lightning damage dice. You must use the new rolls.

Whenever you take cold, fire or lightning damage from a hostile creature, the amulet regains 1 charge.