Give three examples of natural magnets.

Hint: Natural magnets are the magnets that occur naturally and are most frequent due to the partially filled $f$ shell of an atom. These Natural magnets inspired us into artificial magnets which further led to electromagnets which run almost all the electronics in today’s world.

Complete step by step answer:
Three natural magnets are:
-Lodestone
-Samarium-cobalt
-Neodymium-iron-boron (NIB)

The most common among these are lodestones which have magnetic properties but are not very strong magnets as they have lesser energy pull as their f-shell electrons have partially less pull strength compared to others. These natural magnets' strength can be enhanced artificially.

This exists due to incomplete filling of electrons in the $f$-shell of an atom and this can be used to create few metals into magnets by disturbing the stability of their $f$-shell electrons.There are so many ways to create artificial magnets, i.e., using pressure, electricity, using another magnet.

Magnets which are enhanced using electricity are known as electromagnets as these materials are sensitive to electricity and we can use this phenomenon to create electromagnets and control the pull power by using required input of electricity.

Note:Ferromagnetic materials i.eiron, copper, cobalt, etc. which are attracted magnets can be turned into magnets by rubbing one pole of the magnet on one corner and another pole of the magnet on another side which charges the incomplete $f$-shell of ferromagnetic materials will turn this metal into a magnet.