Rusty item

Rusty items are a small class of items introduced in Golden Sun: The Lost Age. They are unique weapons that are extremely weak when first found, but if you have Sunshine the blacksmith in Yallam take a look at a rusty item he will offer to reforge it into the rare weapon artifact it's meant to be. If you do, he will take it and will be done as soon as you leave and reenter the town, at which point his wife will give it to you, for a price of course (though in the English version of the game the price is not stated).

Long Swords
Robber's Blade: An Artifact that increases base Attack by 101. Its Unleash effect, Shred, is an attack that adds 33 damage, is based on the Mars element, and may lower the target's Defense rating by 25%. It is found in a treasure chest in Aqua Rock. Its buy value is 7600 coins and its sell value is 5700.

Soul Brand: An Artifact that increases base Attack by 141. Its Unleash effect, Soul Shatter, is an attack that adds 50 damage, is based on the Mars element, and 10% of the damage done is added to the user's own PP meter. It is found out in the Great Western Sea while sailing, at the southern of the two shallow spots west of Atteka. It is surrounded by a ring of rocks that requires the ship to have the Wings of Anemos attached so it can fly over into it. Its buy value is 11600 coins and its sell value is 8700.

Light Blades
Corsair's Edge: An Artifact that increases base Attack by 90. Its Unleash effect, Lunar Slash, is an attack that adds 25 damage, is based on the Jupiter element, and may lower the target's Resistances by 40. It is found in Lemuria by digging it out of a spot on the ground using the Scoop Psynergy. Its buy value is 6300 and its sell value is 4275.

Pirate's Sabre: An Artifact that increases base Attack by 136. Its Unleash effect, Scorpionfish, is an attack that adds 43 damage, is based on the Mars element, and may inflict Venom on the target. It is found out in the Great Western Sea while sailing, when searching a shallow spot immediately southwest of Osenia. Its buy value is 10600 and its sell value is 7950.

Axes
Captain's Axe: An Artifact that increases base Attack by 95. It does not have an Unleash effect; rather, it can be used as an item while in the inventory of an Adept that is able to equip it (but it does not necessarily have to be actually equipped) to increase an Adept's Defense rating by 25% in battle, though there is a chance its functionality as a Usable item will break and it will have to be repaired to reuse its Use effect. It is found out in the Great Eastern Sea while sailing, at a shallow spot shortly south of the foggy Sea of Time. Its buy value is 6800 and its sell value is 5100, its sell value while broken is 3400, and its repair value is 1700.

Viking Axe: An Artifact that increases base Attack by 137. Its Unleash effect, Stun Bolt, is an attack that adds 47 damage, is based on the Jupiter element, and may Stun the target. It is found in a chest in the earlier portion of Treasure Isle, in an area that becomes accessible once Felix gains the Grind Psynergy in Lemuria. Its buy value is 11000 and its sell value is 8250.

Maces
Hagbone Mace: An Artifact that increases base Attack by 108. Its Unleash effect, Wyrd Curse, is an attack that adds 41 damage, is based on the Venus element, and may Haunt the target. It is found out in the Great Eastern Sea while sailing, at a shallow spot a short ways east of Treasure Isle. Its buy value is 8400 and its sell value is 6300.

Demon Mace: An Artifact that increases base Attack by 115. Its Unleash effect, Evil Eye, is an attack that adds 38 damage, is based on the Venus element, and may inflict Delusion on the target. It is found in the interior portion of Gaia Rock, at the part where there is a long series of one-room multi-exit hallways. Its buy value is 9200 and its sell value is 6900.

Staffs
Goblin's Rod: An Artifact that increases base Attack by 134. Its Unleash effect, Sargasso, is an attack that adds 39 damage, is based on the Mercury element, and may instantly fell the target. It is found in a shallow spot in the Great Western Sea, northwest of Hesperia. Its buy value is 9800 and its sell value is 7350.

Glower Staff: An Artifact that increases base Attack by 126. Its Unleash effect, Flash Force, is an attack that adds 44 damage, is based on the Mercury element, and may seal the target's Psynergy. It is found in the Shrine of the Sea God dungeon, in the portion accessible with the Frost Psynergy. Its buy value is 10100 and its sell value is 7575.