They were very heavy but perfectly smooth,
and would suffer no damage if by accident or malice they were unseated
and rolled off their tables. They were indeed unbreakable by any violence
then controlled by men, though some believed that great heat, such as
that of Orodruin, might shatter them, and surmised that this had been
the fate of the Ithil-stone in the fall of Barad-dur.