Elemental Gem

You can use an action to break this gem, releasing a burst of elemental energy that summons an elemental to you as if you had cast the _conjure elemental_ spell. The type of gem determines the elemental summoned. The gem loses its enchantment when broken. __**Table: Elemental Gem**__ | Corundum | _Fire elemental_ | | -------- | ----------------- | | Diamond | _Earth elemental_ | | Emerald | _Water elemental_ | | Sapphire | _Air elemental_ |

Source: Level Up Advanced 5e · OGL-1.0a · 5.1