The simplest description of charcoal is the cold hard black remains left over after your campfire has gone out. Essentially all the water has been evaporated off (Pyrolysis), along with some volatile constituents, leaving behind the familiar crusty crumbly black chunks. Now charcoal can be made from the bones of animals, or coal, but for medicinal use it has historically come primarily from plant-based sources such as hardwood, bamboo, coconut, or peat. But, what is left after the fire goes out is, apart from a few trace minerals, pure carbon, just like the carbon atoms that make up the soft graphites in a “lead” pencil or the 345 carat diamonds in a golden crown. What makes the carbons different from each other is their distinct physical structures.