The M320 was first introduced in 2004 when Pelikan gave us the Orange Marbled variant.  This was followed up with Jade Green in 2007, Ruby Red in 2010, and Pearl in 2011.  These pens maintain the same M3xx form factor but introduce some rather colorful and exotic finishes.  There is only one trim variant.  The pens all have a black piston knob and section except for the Pearl model whose piston knob and section match the coloring of the barrel and cap.  The caps of these pens match their respective finishes.  There are two cap bands, a trim ring at the section, and two trim rings at the piston knob.  The furniture is gold-plated.  The cap top has a painted one chick logo on the Orange Marbled and Jade Green Models.  Since the Ruby Red was released during the year Pelikan transitioned its Souverän line to the 24K plated cap top, you will find examples of both in that model.  The Pearl release is only found with the 24K plated one chick logo cap top.  The nibs of these pens are two-toned 14C-585 gold and can be swapped with any nib of the M3xx line but not amongst other lines due to its unusually small size.  The barrels on all but the Pearl model have translucency that allow you to gauge the remaining ink level.  Total ink capacity is 0.65ml.

Orange Marbled

Jade Green

Ruby Red

Pearl