Determining if a Material is Magnetic

Q: How do I know if a material is magnetic?
A: Iron is the element that causes magnetism.  Therefore, any material/alloy containing iron MAY be magnetic to some extent. However while all stainless steels contain iron, some stainless steels are magnetic, and others are not. The defining factor of magnetism comes down to the steel’s microstructure. Martensitic stainless steels (which have a ferritic microstructure) are magnetic. Austenitic stainless steels contain nickel and are non-magnetic. Metals containing little to no iron are also non-magnetic. These metals/alloys would include titanium, aluminum, Monel, Inconel, and tungsten to name a few. And of course, ceramics and polymers are non-magnetic as well.