Aerocrystals are hard to come by anywhere in the world.
About
Sneerwell's got the largest inventory of them in the whole West of Quelmar. One kilogram of Aerocrystal material, when powered by a fluxable solution such as Caeruleum, can provide enough anti-gravitous push to support roughly 3 kilograms of material (including the one kilogram of crystal itself, so an extra 2 kilograms). Pendergras Industries is a world leading innovator of the Aeroships which utilize these crystals, which utilized roughly 15,000 GP worth of crystals.
Magical Properties
Magical stone such as Wovenstone (and its shadowed equivalent Fellstone) would be strangely attracted to Aerocrystals, which enhanced its ability to levitate wovenstone-crafted machinery.
Mines
At least one organization, known as the Pradassis Mining Conglomerate, was known to mine and recover aerocrystals from deep within the earth of Isonhound, where their original source was still unknown, interestingly enough, the crystals seemed to be protected by Mezzoloth daemons, perhaps connecting them to some sort of power in Hades.
