Board Thread:Suggestions forum/@comment-34204318-20180322053453/@comment-33185350-20180324194455

98.146.199.122 wrote: Check the FB page I think we can assume that was the inspiration for this thread in the first place. But we’re not just talking about Black Gondor Brick being renamed Númenórean brick, but the actual black stone used to make the walls of Minas Tirith and Orthanc, which is no ordinary brick but practically indestructible.

On the Facebook page the mod team says that Númenórean brick is only a temporary stand in for whatever stone Orthanc is made out of, which will be implemented in some form later. The brick (which will also be craftable on an Umbar crafting table) seems to be nothing special but just a common building material.