A durable kind of ore. Not to be confused with the weapon Orichalcum. オリハルコン [orichalcum] in Japanese.
Orihalcum is a legendary - probably imaginary - metal, in ancient times believed to have existed in Atlantis. It is said to be extremely precious and strong.
Final Fantasy III
Obtain: from showing Unknown Metal to Cid Haze
Use: bring to the Legendary Blacksmith to forge into Ultima Weapon
Description: A chunk of legendary metal
Type: Key Item
Final Fantasy XII
Buy: - (sell: 1,777 gil)
Use: Masamune, Stoneblade
Drop: Deidar, Vishno
Steal: Vishno
Poach: Deidar
Description: This mysterous metal seems to waver and shine like a flame. Some believe it does not even truly exist, and that it is the mere idea of the metal which lends protection.
Grimoire of the Rift

Buy: - (sell: 2,800 gil)
Use: Ayvuir Red, Orichalcum Dirk, Restorer, Vigilante, Wygar
Reward: Yellow Wings in Trouble (once), A Lady's Proposition (once), The Cat's Meow x2 (once), The Dig (once), Goug Nightwatch (once), Through Another's Eyes (once)
Type: Metal, Rank: ★★★
Description: This metal has the strange property of becoming solid only at certain times of the day. Smiths call it the phantom metal, and treat it with utmost care.
Other: is オリハルク [orihalcu] in Japanese instead of the regular version
Final Fantasy Tactics S

Buy: - (sell: 500 gil)
Use: Grand Cannon
Obtain: Nation of Magick Nensa-Ramoi/Gorpo Wind Holes lv60+
Description: A very uncommon metal
Other: is オリハルク [orihalcu] in Japanese instead of the regular version
Crystal Chronicles
Obtain: Conall Curach
Buy: - (sell: 5,000 gil)
Use: ?
Category: Item