flamarina
Насколько я понимаю, основная проблема именно с созданием стали, как таковой.

Из "Так сказал Мартин":

Q: is it the metal that makes the sword so special (provenance, age, etc), or is it the forging (spells, techniques)
Martin: Forging techniques and spells, actually. There is magic involved in the making of Valyrian steel.
Q:In other words, if a smith knew how, could he take some fresh, high-quality steel and produce an equally fine sword?
Martin: Not unless he could work the magic.