Dear Student,
Anthracite and Bituminous are basically two different forms of coal that have many differences. First of all, the two differ in their carbon and sulphur content. Anthracite has more carbon content and less sulphur content than bituminous and is harder than bituminous coal. Also, anthracite is regarded as a metamorphic rock where as bituminous is regarded as a sedimentary rock. Moreover, the amount of volatile substances that are obtained by burning of anthracite coal are much lesser than those obtained by burning of bituminous coal. This is the reason why anthracite is regarded as the highest quality coal.
Regards