Charcoal (Impure)
Impure Charcoal is formed when Flammable nodes burn partially or are heated but do not have space to burn.
Impure Charcoal has a range of different qualities, represented by how "black" the node looks.
Pummelling Impure Charcoal with a Hatchet (from any side) will break it into a number of Ash Lumps and Charcoal Lumps, based on the quality. The latter can be used to make Pure Charcoal.