What is the code for Lustrious orb on Pokemon diamond?

You can't directly input a code to get a Lustrious Orb in Pokémon Diamond. There are no cheat codes or codes that give you specific items in the game.

However, here's how you can obtain a Lustrious Orb in Pokémon Diamond:

1. Defeat the Elite Four and become the Champion.

2. After becoming Champion, you can find the Lustrious Orb in the back of the room with Cynthia, the Champion.

Remember, the Lustrious Orb is a very important item in Pokémon Diamond, as it is required for the evolution of Palkia from Azelf.