|“||They are wrought of ithildin that mirrors only starlight and moonlight, and sleeps until it is touched by one who speaks words now long forgotten in Middle-earth.||”|
–Gandalf, II, A Journey in the Dark
Ithildin is a material, originally used by the dwarves of Khazad-dûm and the Noldor elves settling in Eregion to make inscriptions and decorations that can only be seen under moon light, much like moon runes. It was added to the Mod in Public Beta 30.
The word ithildin is Sindarin and means "moon-star".