* Origin: Rocks are formed by geological processes, like cooling magma (igneous rocks), pressure and heat (metamorphic rocks), or the accumulation and cementation of sediments (sedimentary rocks). Coal, on the other hand, originates from the accumulation and decomposition of plant matter over millions of years.
* Composition: Rocks are primarily composed of minerals, which are naturally occurring inorganic solids with a defined chemical composition. Coal, while containing some mineral components, is predominantly made of carbonized plant material.
* Fossil Fuel: Coal is classified as a fossil fuel, formed from the remains of ancient life. True rocks don't contain fossil remains.
Therefore, while coal shares some characteristics with rocks (it is solid, layered, and found in the Earth's crust), its unique origin and composition classify it as an organic sedimentary rock rather than a true rock.
