What are the effects of charcoal?

Answer 1

Charcoal is used by artists to make sketches, and is a surprisingly expressive medium.

Activated charcoal is used for its chemical adsorbency, in medicine, and was used in earlier gas masks.

Charcoal was also used on very old household smoothing irons. These ones will have a cavity inside for the charcoal, and they have an opening at the front, perhaps 30 - 40 mm in the front. Movement of the iron will supply enough draught to keep the charcoal burning.

Charcoal was used in early iron smelting. Crushed charcoal was a component of gunpowder.

So, its properties were a black marking material, a chemical adsorbent, or a heating medium.