Arcane Dust

Arcane dust is a substance found on the remains of magical creatures  (e.g. memphits and elementals). It can be an array of different colours depending on the creature it originated from. 2 ounces of arcane dust can be used as an additional material component when casting spells that deal damage. When used in this way, you can choose to reroll one of the rolled damage dice and must keep the second result.