A precursor of the graphite pencil is the silverpoint. A silverpoint is no more that a metal wire. It can be made of silver, gold, copper just about any metal. The lines they produce are almost identical to pencil, but also change in color over time through oxidization. The only constraint is that the paper needs to be primed before the mark will show. Leonardo Da Vinci did most of his drawings with such a device. One advantage is that they remain sharp for years.

You can test the line such a device makes by taking a coin and dragging it over a painted surface, like a wall.