The Blacksmith at the Arthach Palace Ruins can be asked about "some interesting diagrams", but these can only be deciphered by a grandmaster, something this smith is not, alas.
Geralt can also mention a guy named Straggen (who happens to have been burned by druids, apparently).
The blacksmith will appear once the Arthach Palace Ruins have been liberated from the Hanse bandits. He mostly sells runestones and crafting components.