The absolutely stunning North American exclusive Dark Teal Tango Imagination from Waldmann is here.
Waldmann engraves the sterling silver body and cap, then applies colored lacquer over the resulting pattern. To let the silver come through, they shave the lacquer down very thin and then apply clear lacquer on top of that to protect the finish. What you are left with is a stunning pen which lets light give the illusion of the engraving dancing on the pen.