Metallurgy is a material with high carbon and few impurities that is used as a fuel. Coke is a solid carbonate material that is obtained from low ash and low sulfur bituminous coals.
The coke that is obtained from coal has a gray color and is also hard and porous. Of course, coke also exists naturally, but the most used coke is the coke made from coal by humans.
Special coals are used to produce metallurgical coke, and the properties of the coal determine the properties of the produced coke.