In Pokémon Legends: Arceus, when the Adamant Crystal is used from the satchel on Dialga, it switches it between its normal form and Origin Forme.
In Pokémon Scarlet and Violet, if a Dialga is holding an Adamant Crystal, it changes to its Origin Forme. Additionally, it boosts Dialga's Dragon- and Steel-type moves by 20%.
||When used on Dialga, this large, glowing gem wells with power and allows the Pokémon to change form.
||An item to be held by Dialga. This large, glowing gem wells with power and allows the Pokémon to change form.