The closer the object is to the magnet or electrical current, the more powerful the magnetic effect. The presence of iron in a mineral is responsible for the magnetic properties of minerals in virtually all cases. Ferromagnetism , or strong attraction to magnetic fields is exhibited in only few minerals, notably magnetite and pyrrhotite. Paramagnetism is weak attraction to magnetic fields. The attraction is usually discernible, but it may be so weak that it is undetectable.
Most paramagnetic minerals become strongly magnetic when heated.
A small number of paramagnetic minerals, such as platinum , are not essentially paramagnetic, but contain iron impurities which are responsible for the paramagnetism. However, some specimens lacking iron also exist, and these are not paramagnetic. Some examples of paramagnetic minerals are hematite and franklinite . Only one mineral, bismuth , is diamagnetic , meaning it is repelled from magnetic fields. Another property, which is unnamed, is attraction to magnetic fields when heated .