How do I get a coal?

[Casual]

I have read that I can either build a Tar Kiln (but it can take up to few days, which I am not interested in) or find a coal boulder (though all what I find are basalt boulders). So where do I search for these coal boulders or is there some other and faster way to get coal?

[VDZ]

The amount of time it takes for a tar kiln to make coal depends on the amount of blocks/boards you put into it. A batch of 6 blocks finishes within 2 hours (probably closer to 1 hour than 2 hours) and nets you 12 coal, enough to smelt one batch of ore. Black coal can be gotten from rare coal boulders, or mined from caves (if you manage to find a coal node).