Crystallize Armor

 As an action, you touch a willing creature, and their armor or clothing is quickly sheathed in a layer of translucent, jagged crystals. For the next minute, the crystallized armor grants the wearer resistance to nonmagical bludgeoning, piercing, and slashing damage.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the wearer's AC increases by 1 for each slot level above 2nd.