Jet, a hard, black, bituminous lignite, capable of an excellent polish and easily carved, hence useful for trinkets and ornaments, which have been made of it from very early times; is found in France, Spain, and Saxony, but the best supplies come from Whitby, Yorkshire.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Jesus Christ * Jetsam