Gallium

 A rare metallic element, found combined in certain zinc ores. It is white, hard, and malleable, resembling aluminium, and remarkable for its low melting point (86° F., 30° C.). Symbol, Ga; at. wt., 69.9. Gallium is chiefly trivalent, resembling aluminium and indium. It was predicted with most of its properties, under the name eka-aluminium, by the Russian chemist Mendelyeev on the basis of the periodic law. This prediction was verified in its discovery (in 1875) by the French chemist Lecoq de Boisbaudran by its characteristic spectrum (two violet lines), in an examination of a zinc blende from the Pyrenees.  [Webster 1913 Suppl.]