OOC: looking back at the thread, I think we've pretty much established that we don't know where it is (failed int checks etc).
Darwin looked glum. He remembered this great-uncle in-law, from a rock gnome clan, and his "library" - a giant pile of scrolls, tablets and books. Oh his great-uncle knew where everything was... but no one else did! Did the same thing occur here? He shuddered... but brightened suddenly.
"Hey, we have pieces of the maps... could we use some kind of divination magic to link it to the missing piece? Like a mystical bond or somesuch?"
Darwin looked hopefully at his companions... who knows what wonders they could do?