Diego explores the martial arts world in search of weapons that might be made with precious metals. He hits a dead end with a master sensei, but the sensei refers him to an ancient weapons dealer. Knowing that marine testing equipment was made with precious metals in order to withstand saltwater corrosion, Rich visits a warehouse that turns out to be a treasure trove of old test equipment. And Dave visits a gold mine in search of crystallized gold, one of the rarest forms of gold on the planet.