The Vault by Boyd Morrison
What if Midas really had the touch that turned things into gold?  What if after centuries the touch of his mummified remains still had the same effect?  What if the directions to the tomb were found yet the evil mastermind couldn’t decipher them?  He’d kidnap an expert in mechanical engineering and an expert in the classics and persuade them (read: threaten their loved ones) to help him find the treasure.
From Puget Sound to the old aqueduct tunnels under Naples our team of treasure hunters is on a race against time to find the vault.  If you like adventure books that travel the world following clues (like Steve Berry, James Rollins and Andy McDermott) you will probably enjoy this one as well.  Fun on audio because the narrator does some great accents.  I especially liked his Scottish brogue and his American Sean Connery sound-alike!
The science behind the Midas touch, the ability to change matter to gold, is a fascinating one.  Morrison really put his thinking cap on to come up with this one.