If held by a Camerupt, allows it to Mega Evolve into Mega Camerupt if its Trainer has a Key Stone. Each Trainer can only Mega Evolve one Pokémon per battle.
Unaffected by item negating effects (such as Embargo and Klutz). Item manipulating effects (such as Trick and Fling) cannot give Camerupt a Cameruptite or remove a Cameruptite from Camerupt.
Outside of battle
If held by a Camerupt, allows it to Mega Evolve into Mega Camerupt when it performs a Spectacular Talent during a Pokémon Contest Spectacular while its Trainer has a Key Stone. Camerupt will remain a Mega Camerupt until the Talent Round ends.
The player can obtain the Cameruptite by completing the Competitive Stage available in Week 15 of the event rotation.
The Cameruptite was also available as a prize during the Mega Camerupt Competitive Stage. This Competitive Stage ran on both the Nintendo 3DS and Mobile versions from November 22 to 29, 2016 and October 10 to 17, 2017.
The Cameruptite enables the following Mega Evolution:
Erases Pokémon and disruptions around two spots you tap. Erases five tiles in a + shape surrounding each spot. Does not activate if the foe is defeated. Only gives 3 seconds to tap. Can erase fewer than 2.