Why is Coal not classified as a Mineral?
Coal is not a mineral because it does not qualify to be one. A mineral is made of rocks. It is non-living and made up of atoms of elements. Coals on the other hand are carbon-based and came from fossilized plants. By just looking into the origin of coals, these are not qualified to be minerals because they come from organic material and it has no definite chemical composition.
Minerals are not formed from living things such as plants or animals. They are building blocks of rocks and are formed thousands of years ago. Coals on the other hand came from dead plants and animals. The coals are formed when these living creatures will decay. Again, it takes thousands of years to form a coal. Although minerals and coals take a lot of time to be formed, they are of different origins.
To be classified as a mineral, a substance must have a crystal structure. It must be a solid crystal such as diamond and gold which has the same chemical makeup and an orderly arrangement. Its crystal structure is an indication that a mineral and its composition can be expressed in a chemical formula.
Coal may be a rock but it does not have a crystal and definite structure. It doesn’t even have a definite chemical component. It can only be formed when plant matter accumulates at the bottom of the sea or any body of water. The mud or water will protect these remains and will be metamorphosed into coal. This will turn into a solid material is now used as fuel .
Coal is only a mineraloid which look like a mineral but actually it does not meet the criteria of a true mineral. Mineral is organic which is made up of hydrogen and carbon. Coal, as explained earlier came from plant remains which has a hydrocarbon structure that’s why it is always mistaken as a mineral.