Calloc is not near Storm Port, and the mage in the Inn of Blades has nothing to do with the dryad. If you give her the special flowers found at the end of a long valley north of Libras, she'll tell you of a treasure you can get near Calloc, which, unfortunately, you can't get in the unregistered version.
Oh, and the metal lumps are actually Mithral, and can be either traded for a couple of spells (Summon Beast and Conflagration) or saved to me made into a Mithral Broadsword later in the game.
Urrr, I think your hidden treasure is just another thing from Jeff to get our goat, kind of like Erika's back room.