The wood used in the pen is 5400+ yr old Ukrainian Bog Oak that has been lying at the bottom of rivers at the depth of 3-7 metres, devoid of oxygen. As a result, the oak acquires unique physical properties: firmness, longevity & a unique color; very dark black & charcoal; with some nice rays & flecks. The iron reacts with the tannin in the oak to cause the natural black staining. Usually the oldest pieces are the darkest.