This is anthracite coal, No. 5 sort, from Pennsylvania. It is sold in one pound bags.
Anthracite coal, or hard coal, has the highest carbon content, the greatest hardness, and the fewest impurities.
This is "No. 5 coal". No. 5 is a measurement of size, not content. The standard sizing of No. 5 coal is 3/64 inches (1.19 millimeters) or smaller. Some random pieces measured 0.56 inches (14.31 millimeters).
The No. 5 is fine coal that can be used for water filtration and waste water treatment.