How do platinum-group metals differ from gold-group metals in hardness and melting point?

Members of the platinum group generally differ from those in the gold group—which includes gold, silver, and copper—by being harder and having higher melting points.1

While gold-group metals are characterized as being rather soft, ductile, malleable, and sectile, the platinum-group metals exhibit a wider range of mechanical properties. For instance, while platinum and palladium are relatively soft and ductile, other members of the group, such as osmium and iridium, are noted for their extreme hardness and brittleness. Overall, the platinum-group metals are recognized for their high melting points, which contribute to their utility in high-temperature applications, such as in crucibles and thermocouples.12345