A briquette (or briquet) is a block of flammable matter which is used as fuel to start and maintain a fire. Common types of briquettes are charcoal briquettes and biomass briquettes. Constituents of charcoal briquettes Charcoal briquettes sold commercially for cooking food can include: Wood charcoal (fuel), mineral char (fuel), mineral carbon (fuel), Limestone (ash colorant), Starch (binder), Borax (release agent), Sodium nitrate (accelerant), Sawdust. Some briquettes are compressed and… (More on Briquette)