"Among the substances that are dug up because they are useful, those known simply as coals are made of earth, and they are set on fire and burnt like charcoal. They are found in Liguria, where amber also occurs, and in Elis as one goes by the mountain road to Olympia; and they are actually used by workers in metals."
– Theophrastus of Eresos, On Stones
Coal is essential to the mining and metalworking efforts of a colony, and can also be used to fertilize fields. Coaling allows you to construct and light Coal Clamps, which burn blocks of wood into charcoal.