Board Thread:Suggestions forum/@comment-34204318-20180322053453/@comment-31507215-20180323183014

If we are being super lore-accurate, then I don't think this should be obtainable at all (aside from maybe cheats) and would only naturally generate in Orthanc and Minas Tirith.

If we aren't being absolutely lore-accurate, I would suggest something like utumno bricks, in that you must go someplace special and would need a special tool to mine it.

My preference would be that this rock would be found EXTREMELY rarely below y15-ish in the Misty Mountains, the Forodwaith Mountains, and the Mordor Mountains, slightly less rarely in Utumno, and semi-rarely in the Roots of the Mountains (from Sir Lazuli's suggestion). It would only be mine-able with a Numenorean pickaxe, found extremely rarely in ocean ruins.