[kronckew]

carbon steel loses it's magnetism when heated, an effect used by smiths when heat treating - hardening. the temp at which the steel is no longer attracted to a magnet is the temp at which it should reach before it is suddenly cooled in oil or water (or a slave). the experienced smiths know when that point is reached by the color or the steel. any magnetism after that has been re-added. magnetic sword holders were popular for wall hanging, which imparts magnetism. sitting in the earths magnetic field for an extended period of not being moved will magnetize steel (or CRT TV screens). working the steel can also do it. i remember a teacher taking an iron rod and demonstrating it was not magnetized. he then gave it a few good whacks on one end with a hammer and then demonstrated it would then pick up iron filings. (he then demag'd it with an AC coil like that which was used to demag TV screens).

pen nibs are usually a high carbon steel plated in gold (or platinum for the expensive ones). that makes them resist corrosion from the ink and keeps the writing smooth over it's life time. the 'brass' nibs are likely just gold plated steel. gold, brass, copper is not magnetic or attracted in a constant magnetic field unless there is an electric current going thru it, like in a copper wire coil on a motor...