Where to get the amulet coin in xd?

In Pokémon XD: Gale of Darkness, you can obtain the Amulet Coin by defeating the Trainer called "Duking" in the Orre region. He is found in the Pre Gym in Pyrite Town. After defeating him, you will receive the Amulet Coin as a reward, which allows you to double the prize money you earn in battles.