Charm of the Gem

As an action, you create a spray of 4d10 gems in a 30-foot cone originating from you. Each creature in that area must make a DC 15 Dexterity saving throw. On a failed save, a creature takes an amount of bludgeoning damage equal to the number of gems created. On a successful save, a creature takes half as much damage. The gems remain after the effect ends, and each one is worth 10 gp. Once used three times, the charm vanishes from you.