Master Ore is a quest item from The Legend of Zelda: A Link Between Worlds. Four specimens of this rare ore can be found hidden throughout Lorule, mostly in dungeons. When two are collected, the Master Sword may be tempered by the Blacksmith in Hyrule, creating the Master Sword Lv2. If another two chunks are collected, the Master Sword Lv2 can be tempered by Lorule's Blacksmith, and Link will obtain the Master Sword Lv3.
Master Ore is found within the dungeons Thieves' Hideout, Skull Woods, and the Dark Palace, as well as the Graveyard.