Where is Coal Found? | Sciencing
Apr 24, 2017· Coal is a mineral that has no fixed chemical formula. It contains various amount of these five elements: carbon, hydrogen, nitrogen, oxygen, and sodium. The hardest form of coal, antracite, is 98% carbon, but only 2% of the coal that is mined in the United States is anthracite. Bituminous coal is the next hardest and lignite is the softest.