Veinstone
Veinstone is from The Deeping. Corrupted stone, it has a strange smell until exposed to sunlight.
Mining it triggers vibrations in the stone around it, creating painful vibrations. It’s painful for the Ducateon, so they do not quarry it. Dwarves, not AS sensitive, use their improved stone senses and mining skills try to quarry it, but only rarely. Black stone, the veins are red in the dark, white when exposed to prolonged sunlight. Veinstone corrodes iron and steel, weakening, dulling and blunting it. It keeps out magic scrying and teleportation. It is thought to be a form of Entrophy.