Chapter 4: On the less common stones

3. _Gagates_ (jet) was first found in Cilicia, thrown up by the water of the river Gagates. Whence it was named, although it is very abundant in Britain. It is black, flat, smooth, and burns when brought near to fire. Dishes cut out of it are not destructible. If burned it puts serpents to flight, betrays those who are possessed by demons, and reveals virginity. It is wonderful that it is set on fire by water and extinguished with oil.

19. _Amiantos_ (amianth) ... resists all poisons, especially those of the magi.