[Solomon's only response to the first remark is a blithe smile. He will naturally test your aim in further surprise live-fire exercises, Stark. At that, though, he drums his fingers against the arm of his chair.]

I can manufacture portals between here and the Dreaming plane. Obsidian and white marble are required elements for a stable doorway. Could you manufacture a stone with a same or similar density, solidity and, above all, colour, to white marble?