Originally Posted by DrIsotope

It wasn't magnetic-- you made it magnetic by applying a magnet. This is some quantum-level stuff, ya'll. From Scientific American:

"A piece of ferritic stainless steel is typically unmagnetized. When subjected to a magnetic field, however, it will become magnetized and when this applied magnetic field is removed the steel remains magnetized to some degree. This behavior is a consequence of the steel's microstructure. Specifically, in its natural state ferritic steel consists of small regions called magnetic domains, which are fully magnetized, but in general the direction of magnetization is different in each domain. As a result, the sum total of all the domains gives the piece a zero magnetic moment. An external magnetic field orients these magnetic domains. Depending on the steel and the applied field, the orientation is achieved by a combination of selective growth or shrinking of particular domains and the rotation of magnetization within the domains. If the applied field is sufficiently strong, the steel will retain a significant fraction of its magnetization as long as the steel has an adequate number of imperfections that keep the domains from rotating and growing or shrinking."

Also, Zero Magnetic Moment would be a pretty great band name.