Coal
It is a a flammable black or brownish-black sedimentary rock with a high carbon and hydrocarbon content. As coal takes millions of years to create, it is classified as a nonrenewable energy source. Since it was formed from the remains of vegetation by carbonisation method, coal is also called a fossil fuel.
Coal can be used to obtain by-products such as coal gas which is obtained as a by-product during the processing of coal to form coke, and is used as a fuel. Coal Tar is a black thick liquid with an unpleasant smell obtained by the processing of coal.
