Speaking of coal, I would never, ever buy "coal" again!!!
Firstly nothing but nothing looks more like coal than real coal.
In my US modelling days, I had a 70 car coal train and therefore got through a lot and tried all the commercial varieties.
What I have been doing for a while now though is, on my next visit to a preserved railway, there is often loose coal lying around the loco areas - I do actually check with staff by saying I want a small piece for my model railway and they say "help yourself"!
You only need one small lump!
Wrap it in a cloth, plastic bag etc and break it down with a hammer! Sieve the residue, graduate and viola! Tons of coal to last for ages!

Another one!
Back in my Austrian days some 24 years ago now(!) I used the contents of dried used tea bags as ballast! It was already a decent colour, good texture and didn't add to the drumming effect you get with real stone ballast. I have to admit, I can't swear as to it's "accuracy" but it seemed realistic back then!
Pröst!
John E.