An IV Stone is a consumable item which has the ability to change one of your Pokémon's IVs to 31 in the earlier parts of the game. Once the player gains access to the end-game content, they will also be able to use an IV Changer who sets any IV to 30 instead.
IV Stones can be found in caves and from the Pokéball in the player's Secret Base. Once the player obtains the final Secret Base upgrade they will be able to buy them from a Mart Worker for $10,000 each.
A beautiful stone that is said to have mystical powers.