Research

Whilst at Formby beach the other day we came across this odd stone that was easily being rolled around by the waves. Once we had picked it up it had us rather flummoxed as to what it was. It was light, had no odor,  no smell and had rather curious white markings. 
After a bit of research it turns out to be Sea coal which is a name by which mineral coal was formerly designated in the south of England, in distinction from charcoal, which was brought by land.
See extras for close up shots.