Dark Vein is the crystalline structure forms in the deep, around places where the weave is thin between spheres and the Well of Shadows of Nightmaria borders the real world. It is very valuable in summoning and providing sustenance to prevent diminishing for denizens of those places brought forth. Those of lesser natures exploit such finds, whilst most discoverers destroy the find – exposing it to sunlight and reducing it to dust.
Exposure: 24+ hours exposure = Constitution check or -1 HP permanently