Fossil shown is actually 4 inch long, and found as an erratic on the beach.

Identification is different to jet, because this piece of wood has been fossilised differently.

Different environments, different temperatures and an abundance of different minerals all change how an item is fossilised. Any organic specimen decays and leaves an encased space were the specimen was, what fills that space varies from area to area.

Just like jet this is lighter than an average piece of rock, but not as light as jet.