Amulet of Embrittlement

This amulet is fashioned from a small glass ampoule secured around the neck by a fine metal chain. Contained within the ampule is a fluid that becomes frozen once all uses of this amulets feature are used. While wearing it, you gain the following benefits.

Spellcasting Focus. You can use this amulet as a spell casting focus.

Arcane Embrittlement. When you deal damage to a creature or an object with a spell or cantrip, you may choose to expend a use of this amulet and change the damage type of the spell to cold. You may use this feature a number of times per day up to the number of your proficiency bonus. You regain these uses after a long rest.