Why gold jewellery cannot be made in 24 karat pure gold?

Gold is a soft metal and has to be hardened to make jewellery out of it which is wearable and durable (doesn't break easily) as well. Gold is generally mixed with silver, copper to add strength to the metal. As other metal is mixed with 24 karat pure gold the purity of gold decreases from 24 to 23 karat, 22 karat and so on depending on your requirement and type of jewellery to be made.