The distribution of coal on basis of carbon content are as follows-
1=lignite ,it contains 45-75% carbon,it is indeed soft and has high moisture content.
2= bituminous coal has 70-90% carbon content and is largely used for commercial purposes ,it is black and emanate lot of smoke and leaves ashes.
3= anthracite has 90-95% carbon content ,it is indeed considered as the best and highest ranking coal. it has less impurities and less smoky .