I myself just got my first Vulcan weapon. ((Vulcan Blade))
This introduced me to this weapon needing Vientiane Stones. Yes I have clicked the question mark under the tabs for Vientiane Stone, Vientiane Stone Synthesize, and Vientiane Stone Equipped Overview to read about those sections. It however did not explain where to get these stones. Can anyone throw some knowledge my way and possibly anyone else who happens to run into this issue. I have no doubt I will find out at some point when one finally drops but I would rather figure this out now to possibly speed up this future encounter. Thanks to those who contribute to this knowledge.