that blade is made from Damascus steel. The method of manufacture was lost a long time age and only recently has the process been rediscovered. apparently the organic looking pattern on Damascus steel can only be produced if a small amount of vanadium impurity is present. As long as the smiths could get the right ore they could make the blades. But when the ore ran out they couldn't make it anymore due to no vanadium. Scientist only recently discovered vanadium in Damascus steel.
http://www.tms.org/pubs/journals/jom/9809/verhoeven-9809.html


