Black Orb

The Black Orb is an item required to pilot Lemurian ships. In order to utilize the orb, a fairly proficient psynergy user(Not necessarily an Adept) must be commanding the ship, and the orb must be paired with the specific ship it belongs to.

In Golden Sun, Isaac can first receive the Black Orb at Idejima if he goes there with Iodem and they spot Saturos and Menardi's ship. Iodem mistakes it for Babi's ship, so he hands Isaac the orb and instructs him to use the orb to raise the ship. Because of the confusion as to the ships identity, Isaac is unaware that the orb will be useless in commanding it, when it inevitably fails, Iodem takes it back from Isaac, holding onto it until later in the game.

After clearing Venus Lighthouse and coming back to Lalivero, Isaac will then receive the Black Orb from Iodem, and this time, he keeps it and goes to the building where Babi's ship is being kept. When using the Black Orb, Babi's ship rises and the ending of Golden Sun plays.

In Golden Sun: The Lost Age, Piers has his own Black Orb to pilot his ship. It is taken away by the people of Madra when they jail him, suspecting him to be one of the Champa pirates. It is then stolen by Kibombo warriors. Felix and company travel to Kibombo and help Piers to reclaim his Black Orb, then after visiting the Madrans, they can go to Piers's ship and make their way to the lower deck, where they use the Black Orb to activate the ship and it can sail. Upon using Piers's black orb on the pedestal in the lower deck, it disappears from the inventory.

Oddly enough, when Isaac rejoins you at Contigo, he may have the Black Orb in his inventory depending on whether you transferred or not, but it is now a useless item and may be seen as a waste of inventory space

The Black Orb is a Key Item, which cannot be sold in shops. In the second game, it is referred to as the Black Crystal, but this is merely due to inconsistent translation, and they are in fact the same item.