The point at which a metal liquefies. This point must be reached if a metal object is to be cast. In antiquity, gold, silver, copper, and lead were all melted and cast, but the melting and casting of iron was not achieved until the medieval period. Melting points are as follows: tin, 232? C; lead, 327? C; silver, 960? C; gold, 1063? C; copper, 1,083? C; iron 1,525? C.