In many places, soft/bituminous coal is hard to come by, but anthracite/hard coal is more readily available. In the USA, many Tractor Supply Company (TSC) stores will carry anthracite, usually in "nut coal" or "rice coal" sizes. This can be used for forging, but it presents some challenges. This has been discussed elsewhere on IFI; this post is an attempt to put the bulk of that information in one place.
As noted below, bituminous coal, coke, and charcoal are all superior to ant