Back about 2000 years ago, the Greek scientists were becoming fascinated with magnetism when they stumbled upon lodestones, a naturally occurring magnet.
Lodestone is a piece of magnetite, an iron oxide, which produces a strong magnetic field. Now, to be clear, not all magnetite is magnetic (it won’t stick to your fridge by itself) but being a type of iron, all magnetite is attracted to a magnet (technical word: it’s ferrimagnetic).
The creation of a lodestone (magnetized magnetite) is still a bit of a mystery, but the leading hypothesis is that the magnetic properties were picked up after being struck by lightning. It’s sort of a geological superhero origin story. This theory is supported by the fact that a lodestone has never been found very far from earth’s surface.
The word magnet originates from Magnesia, which was a region of Greece where these original lodestones were popping up.
Magnetite lodestones are one of only two minerals that have been found to be naturally magnetized on earth. Which begs the question; how do the real estate agents and plumbers manage to get their hands on so many lodestones?
Most of the magnets we encounter on a daily basis have been artificially magnetized. You can start with any ferromagnetic material. (most commonly ferrite, a ceramic compound containing iron oxides) The simplest way to turn that into a magnet would be to rub it against something that is already magnetized in the same direction many times. (it’s sort of like you are “combing” the electrons)
To manufacture the strongest magnets, the material must be heated above the Curie temperature, which varies depending on the material, putting it into a receptive state. It’s then subjected to a strong electromagnetic field. As it cools, the magnetism remains in the material. If it’s ever re-heated past that Curie temperature again, it could lose it’s magnetic strength. I learned this the hard way when trying to use a hot glue gun on rare-earth magnets.
Now, this is just the tip of the iceberg for the fascinating science behind magnets. There is a lot to think about next time you go to clip up your grocery list.