The outer rind of the papyrus was converted into ropes; and this fabric was found to be peculiarly adapted for immersion in water.
The mineral treasures of the Empire were various and abundant.

It has been noticed already that Persia Proper, if we include in it Carmania, possessed mines of gold, silver, copper, iron, red lead, orpiment, and salt, yielding also bitumen, naphtha, sulphur, and most probably common lead.

We are further informed by ancient writers that Drangiana, or Sarangia, furnished the rare and valuable mineral tin, without which copper could not be hardened into bronze; that Armenia yielded emery, so necessary for the working and polishing of gems; that the mountains and mines of the Empire supplied almost all the varieties of useful and precious stones; and that thus there was scarcely a mineral known to and required by the ancients for the purposes of their life which the Great King could not command without having recourse to others than his own subjects.

It may be likewise noticed that the more important were very abundant, being found in many places and in large quantities.

Gold was furnished from the mountains and deserts of Thibet and India, from the rivers of Lydia, and probably from other places where it is still found, as Armenia, Cabul, and the neighborhood of Meshed.