A porous form of carbon produced by the destructive distillation of organic material. Charcoal from wood is used as a fuel. All forms of charcoal are porous and are used for adsorbing gases and purifying and clarifying liquids. There are several types depending on the source. Charcoal from coconut shells is a particularly good gas adsorbent. Animal charcoal (or bone black) is made by heating bones and dissolving out the calcium phosphates and other mineral salts with acid. It is used in sugar refining. Activated charcoal is charcoal that has been activated for adsorption by steaming or by heating in a vacuum.