You know that pencil "lead” isn’t, right? While you could write with a chunk of lead it wouldn’t look very good (or be very healthy). That dark gray stuff is graphite. This plentiful form of carbon has turned into the ideal material for writing on paper (due to its softness), for electrodes (for its excellent conductivity), for making crucibles (because it’s practically unmeltable) and for many, many other applications.

Precision cut into little, laser-engraved wedges they also happen to make beautiful presentation pieces :-)