Board Thread:Suggestions forum/@comment-32926935-20170916025558/@comment-25754873-20170928191136

High King Ithilion wrote: Adamant is also a word used for strength. So it's an unbreakable tower. No particular substance that we know of, but it theoretically could be adamant.

Ithilion, Discussions Moderator (Auta i lómë) The stone that made up the Orthanc and the 1st wall of MT :^)