Seven metals in Alchemy: gold, silver, mercury, copper, iron, tin and lead. Each of these was linked to a particular planet: gold – Sun; silver – Moon; mercury – Mercury; copper – Venus; iron – Mars; tin – Jupiter; lead – Saturn. Seven days of the week were also associated with the planets and metals. It was believed that the planets and metals existed inside every human being. The balance between these made up the human temperament, personality and even physical appearance. It was believed that there are seven different types of person, linked with the seven planets or metals.