Instructions
Defeat the dungeon on Aqua Rock, and get the parch psynergy. This psynergy is necessary to melt some of the frozen pools and items in the next dungeon.
Go to the world map, and run into your ship. Sail to the southernmost island, which is long, thin and icy. This is Thundaria, and the only location on this island continent is Thundaria Tower. Enter the tower.
Choose the middle path in the room with three staircases, solve the moving pillar puzzle then defeat the Mars Djinn in the next room. In the northernmost room, cast reveal psynergyto reveal a hidden room. Enter this room and take the Burst Brooch, which bestows the burst psynergy.