Last Alchemist, The (Destroyer #64) by Warren Murphy

THE STONED GOLD BUG

The Philosopher's Stone. The key to turning base metals into gold. Everyone knew it didn't exist. Except it did. 

And now the last of the alchemists, Harrison Caldwell, had his hands on it and was reaching out to grab the nuclear power that would fuel his dream for bottomless wealth - and create a golden age of hell on earth.

Only Remo and Chiun could stop him...if they could get past the army of the highest paid killers on the globe...if they could survive the attacks of Francisco Braun, the golden-haired murderer, whose reputation for boing the #1 assassin in his deadly trade was well earned... and if they could break the power of the magic metal that reduced governments to servants and turned even Remo Williams into its slave...