[From Gagas, a town in Asia Minor.] A hard black mineral, easily cut and carved, and capable of receiving a very beautiful polish. Jet appears to be a kind of bituminous coal, but much harder and smoother than that used for burning. Much of it is found near Whitby, Yorkshire, where it has been worked for centuries. It is made into buttons, mantel ornaments, necklaces, earrings, brooches, bracelets, and other trinkets. Jet is also found in France and Spain, and in these countries it is made into rosary beads, crosses, etc. Sometimes called black amber. tet'ty. A landing-place carried out so far that vessels may discharge their cargoes at all states of the tide ; a breakwater for the protection of river or harbor mouths. Jetties are built out in Dairs into the ocean so as to confine the outflow of streams and prevent the formation of bars. The Mississippi jetties, begun in 1875, deepened the South Pass of that stream from 141/2 to 23 feet, the confined water sweeping the mud from the bottom.