Subject: Strange magnetism of graphite

One of my friends claimed that he did an experiment and found that graphite 
was slightly magnetic. I didn't believe him, but after reading about 
paramagnetism and diamagentism, I decided to do an experiment as well. Using 
0.5 mm "lead" for mechanical pencils, I balanced a piece carefully over the 
edge of a book and applied a magnetic field consisting of 54 "Geomag" magnets. 
As I moved it closer, the graphite suddenly moved away from the magnet (I 
tried the other pole of the magnet and it was also repelled). I concluded that 
graphite was diamagnetic. This was, in fact, what I had expected, since 
pyrolitic carbon is diamagnetic. I then decided to sharpen a HB pencil, again 
balance it carefully over a book, and apply a magnetic field. To my surprise, 
it moved closer to the magnet (again, I tried both poles). What could possibly 
explain this?

Re: Strange magnetism of graphite