Anthracite is the hardest and
purest coal available and comes from eastern
It is a little more difficult to get it started and keep it burning. To burn the larger sizes like Stove size you will need to have a very large hot fire going. The smaller sizes like Nut are best all around size for all but the coldest weather. The Anthracite is a free burning coal and will not clump together.
Bituminous is the middle hardness of coal with Lignite being the softest. Bituminous is a very easy coal to get started and to keep burning but it has more impurities so it burns with a more yellow flame and has a little more smoke and odor. It seems to burn good in most wood burners and burns hotter than wood in most cases. To burn just coal you will need to have grates and be able to get some air underneath or you can load some wood first then a little coal on top. This will extend your burn time since the wood will burn away first.
The Bituminous coal that we have is a Low Volatile coal so it has very little gas and does not puff back much. This coal has a fairly high Coke Button so it will tend to swell up and fuse together as it tries to form coke. It is best to break this up a little with a poker. This swelling and fusing is not to be confused with forming clinkers which has to do with the Ash Fusion Temp. If the coal is burned too hot the ash will fuse together forming a clinker that will need to be picked out.