France, Germany (Wiirtemburg), and Spain have deposits of jet, and it is worked and sold in these countries. Good imitations of the real diamond wedding rings have been used; those in glass are harder, heavier, and colder to the touch, as are also all the black stones, such as onyx, obsidian, and black tourmaline, but various plastics, such as Bakelite, have a close surface resemblance to jet.
The Greeks and Romans knew jet under the name of gagates, and the present term is a corruption of this. The derivation seems to come from the river Gages, where Pliny wrote that the material was originally found. The German term gagat also appears to have the same origin. Other old writers, such as Solinus, mention jet as being found and used in Britain during the early days.