Pitt Charcoal set, 10 pieces Natural charcoal sticks are the oldest sketching and drawing material in the world. The greyish-blue shade glides softly across the paper, rubs and smudges easily, and can be erased without difficulty and repeatedly overlaid. Their blueish hue has always held a fascination, even with the old masters. The charcoal pencils leave a much blacker line. Compressed charcoal with soot and clay give the charcoal pencils their deep black colour and can be produced in different degree of hardness.