Discovered in 1875.. Fun Facts. The color is a silvery-blue. . The melting point is 302.98 K.. Uses of gallium are: photocells and transistors.. The atomic weight, volume, and number: 69.723, 11.8 cm3/mol, 31.. Gallium is often found as a trace element in diaspore, sphalerite, germanite, bauxite, and coal..