I am in the midst of investing my soul into a homegrown campaign world for D&D, and I came upon this idea...Has anyone tried to develop some mechanic/commodity that drives the politics and economies of their world? Take for example oil in today's world, gold in the 15th century, or spice from Dune? One idea I am throwing around is magic...could it be controlled by a select few within a specific geography? Perhaps a race of dweebs inhabiting a mountainous region with active volcanoes that produce crystallized magic that is used to fuel spells or items, for example.
Thoughts/ideas/comments/experiences are welcome