Answer by
HomeschoolMom4 (127)
The marks left would be graphite in either case. However, in the case of a pencil, it is mechanical abrasion that physically scrapes layers from the solid core of the pencil 'lead.' In pens, the marks are left by the flow of a liquid suspension/dye onto surfaces.
Graphite PENS would contain a slurry of microcrystalline graphite in a liquid carrier.