Wondrous item, uncommon

This gem contains a mote of elemental energy. When you use an action to break the gem, an elemental is summoned as if you had cast the conjure elemental spell, and the gem’s magic is lost. The type of gem determines the elemental summoned by the spell. Gem Summoned Elemental Blue sapphire Air elemental Yellow diamond Earth elemental Red corundum Fire elemental Emerald Water elemental Elven Chain Armor (chain shirt), rare You gain a +1 bonus to AC while you wear this armor. You are considered proficient with this armor even if you lack proficiency with medium armor.