> - My experience is that when iron particles rust, they lose their

     > magnetism.
             Too bad iron oxides are still magnetic. At least some of
     them are - I know this because I've trivially witnessed the
     phenomenom. The black oxide Fe3O4 is magnetic. Not sure about Fe2O3
     aka 'rust'.
             "Iron(III) oxide was the most common magnetic particle used
     in all types of magnetic storage and recording media"
             oops, so 'rust' is magnetic too.

   All I know for sure here is that once I ordered a bag of iron oxide
   powder and a magnet wouldn't pick any of it up.  I was looking for a
   magnetic powder.  I didn't note the chemistry if it was present.