You’re correct. Every time you write with a pencil you leave graphene and graphene oxide behind on the paper. You can take a large block of graphite and use scotch tape to pull of large chunks of graphene. Put a neodymium magnet next to it. It won’t move. However, there are non-ferrous elements that can exhibit a response to magnetism. The link below has a good explanation. https://www.nde-ed.org/Physics/Magnetism/ferromagmaterials.xhtml